"I hadn't bargained for such an adventurous life," says Jonathan Raban, at the moment safely hunkered over a bourbon and water (no ice, please) at the Watergate Hotel bar.

In only a few hours two years ago, though, this Englishman had "faced a storm, been nearly drowned in the dark and held at gunpoint," which he recorded in the critically acclaimed "Old Glory, An American Voyage," an account of his 1979 solo journey down the Mississippi in a 16-foot motorboat.

He packs his pipe. "I'm a kind of genuine coward," he says. "As a child, I hated rugged sports like football. I knew if you got close to the ball, you'd get kicked.

"Look," he says, rearing back on the padded bar stool, "I flinch very fast." At boarding school in England, classmates would tease him by "beginning to clench their knuckles. I'd flinch. I'm terrified of heights. I'm terrified of flying."

The voyage "was totally out of character for me. I'm not mad for the out-of-doors. I'm a sedentary city person, totally dependent on the amenities of an apartment in a big city."

Having had no previous experience on the Mississippi, "I didn't recognize there was any danger. I assumed boats are much like small cars. I can drive a car; I assumed I could drive a boat. I was wrong."

The trip, a 2,000-mile odyssey from Minneapolis to the Gulf of Mexico, was an adventure dreamed of 30 years earlier by a 7-year-old lad reading "Huckleberry Finn" on the banks of a stream winding by his father's Anglican church in Norfolk.

Early into the nearly four-month adventure, a drenching afternoon squall had, as Raban puts it, "puckered" the broad face of the Mississippi with rolling waves and sent him scurrying for safety on the Iowa shore. By sunset, though, the wind calmed, and he decided to chance his first nighttime run down-river to a warm room and dry clothes in Burlington.

"I nosed out gingerly, feeling my way through water that I couldn't see."

Suddenly, the bright beam of a spotlight half-blinded him. A siren's blast stridently warned him he was groping in the path of a fast-approaching tugboat. The sound was "as queerly, then scarily, intimate as the cough of a stranger in one's bedroom."

Panicking, he swung his boat around to flee, but not before the high wake caught him broadside, nearly capsizing him and leaving him shin-deep in water. "Blubbering with shock," he beached cautiously at the lighted yard of a run-down wooden cabin on sticks.

Inside, Raban saw two elderly women and a man. Banging on the glass door, he watched as the man slowly picked up a shotgun and leveled it at his chest.

"I yelled that I was traveling down the river, I was English, I had run into trouble, I needed help."

Finally, the trio let him enter, fed him coffee and cookies and drove him to town "where I fell in a heap on the hotel bed in my clothes."

Because he is a coward, says Raban, the Mississippi trip was made all that much more exciting. "One likes the things one fears. It gives you the edge of fright, and fright reminds you you're alive. If I had had more experience, it wouldn't have been so frightening -- or so interesting.

"I'm 39. I love the idea of learning things late. It's so easy to get ossified."

A slight man of average height, he is dressed comfortably in blue cords and a windbreaker jacket. A neatly knotted tie and brown, narrow-brimmed corduroy hat over longish dark hair give him the jaunty air of a grown-up pixie -- a mischievous one, you suspect. He walks in a loose, loping style, obviously accustomed to prowling foreign cities on foot.

This is his first (and very brief) trip to Washington, and he is eager for details about the Watergate Office Building and the Howard Johnson's across the street, even momentarily considering hauling home a bottle of bourbon bearing the famous Watergate label.

At Thompson's Boathouse where he has gone to see the Potomac, he is disappointed to learn, first, there's not enough time for him to take a powerboat out on the river, and second, that the farthest he could get up-river is about five miles, to Little Falls. He gives up the idea of exploring the local waterway and heads back for the bar.

Reviewers have praised his seemingly easy ability both in "Old Glory" and his 1979 book, "Arabia, A Journey Through the Labyrinth," to meet and mingle with exotic types, from Yemeni card players in a native bar he joins for a few hands to Knights of Columbus in Wisconsin, whose picnic he barges into uninvited. These encounters he captures in short, often sensitive but sometimes devastating portraits that have helped win him a reputation as a premier travel writer. "Old Glory" is the the fall Book-of-the-Month Club's main selection.

It is somehow troubling, though, that this ostensibly charming guy can write so harshly about many of the unsophisticated citizens of the bleak river towns who befriended the foreign visitor, took him coon hunting and served up a special meal of squirrel. In Minnesota, a lockmaster offered him a room for the night. His reward is this description of his wife:

"She looked like a retired lady wrestler. Slack-jawed, her eyes hidden behind the thick lenses of her glasses, she filled her outside stretch pants to the last stitch . . . a comedy show was running on the screen. When the audience laughed, Beverley paused in her popcorn eating, gave a perfunctory cackle and said, 'Funny, huh?' to me without moving her eyes from the TV . . . Beverley and I were not hitting it off."

No wonder, as he points out, critics in Illinois' Quad Cities of Davenport and Bettendorf, Iowa, and Moline and Rock Island, Ill., are suggesting they would have been happier now if he had sailed right on by without stopping. "Unfortunately for us," wrote the Davenport Quad City Times reviewer, "the British writer stopped here and sentenced us to 19 pages."

And Sally, the St. Louis woman he moved in with for a bit until marriage threatened, was until recently "on my tail. She'd read my book and was fit to bust. She was really working like the FBI to find me. I was terrified." Back in the United States fora month to film Mississippi footage for American and British TV, "I had Simon & Schuster his publisher call her. They did my dirty work for me.

"She was wounded, she told them. So I rang her up, and we had dinner. We made up, and all her wrath changed. Her mother read the book, though, and told her 'He's got you to a T.' Now she's mad at her mother.

"How are you going to report life," he offers, "if you report it as a series of wonderful people? Some people are repulsive. Some are lovable. The book is subjective. It is how one sweaty traveler happened to find the people on his travels.

"If there's a real villain in the book, it's the person represented by me -- the villain, the victim and the hero. My own justification for writing satirically is that I came out worse off."

That he is being cited as possessing an enviable ability to connect with the high-born and the low-born surprises him. "It isn't an ability," he protests. "It's a kind of desperation. I'm the least sociable person alive. If you set yourself adrift, you become hungry for conversation. You're prepared to talk to anybody, including the town drunk."

Maybe so, but his conversation flows readily, bouncing lightly among a range of topics -- it's doubtful he is ever at a loss for anything to say. The verbal self-knocks, one suspects, are more for satiric effect.

He has been, perhaps, slightly stung by reviews that suggest he hit every bar up-river and down. "You put into port after 70 miles on the river. Your hands are shaking because you've encountered boils and whirlpools and tug washes. Who in his right senses wouldn't hit the first bar?

"I tried to spend a corresponding time in churches. I'm an agnostic, but I love theology -- not so much as it touches God, but as it touches the insides of man. I like the language in which theology is phrased. It is so much more articulate than psychology."

Don't mistake him for a will-o'-the-wisp romantic. Though he writes that he was "haunted by the dream of the Mississippi River" since childhood, it is not a trip, he acknowledges, he would have begun without the firm expectation that a book would be coming out of it.

"Mine is very, very much the writer's trip. If at the end there was no book in it, I might have been sitting in London regretting wasted time. It wouldn't have been significant to me -- except as an amazing kind of error."

He is at the moment anxious to get back to his London apartment for the very pragmatic reason of earning more money. He is a free-lance magazine contributor and writes frequently for British TV. His publisher has picked up his traveling expenses for the past month in America, but that doesn't take care of the continuing household bills.

So far Raban has kept his mood light, bantering. But at one point, he turns serious:

"I watched Reagan on television last night," having been asked to do a newspaper piece on the president."America has never seemed to me a foreign country, until now.

"My first experience with America was being 3 in Norfolk with an American air base at one end of town and a German prisoner camp at the other. The Americans were bigger and pinker and drove by in armored cards, chucking out candy. My mother wouldn't let me stay in the street where I wanted to be begging gum.

"We studied French culture in school. American culture was a gift. It came to you in the form of Coke and Elvis records. I founded a Bill Haley fan club.

"That America, I thought in a vicarious way, I had become a citizen of has turned mercurial, unpredictable. You wake up hearing Libyan planes have been fired at while the president sleeps. In England, our damage with Margaret Thatcher is internal. The world trembles at the edicts of Reagan -- or is it Haig?"

Two years ago on the Mississippi, "It was transparent all the way down-river that people were going to go for Reagan. When the people talked, it sounded tough -- about how America had been humiliated -- but it was sad talk. It amounted to a bottoming out of American self-confidence. America's sense of identification had been bruised."

In the book, he quotes an American Legionnaire from Wabasha, Minn., who shook Jimmy Carter's hand on a campaign swing: "He was stiff with fright. All he was thinking was someone was going to shoot him. Up on those bluffs above town . . . This was the president of the United States, and . . . gosh, he was just a real scared man. I mean I felt sorry for the guy . . . I couldn't vote for a man I felt sorry for like I felt sorry for Jimmy Carter."

Shifting on the bar stool, Raban attempts to light a miniature pipe, finding one more thing about America that irritates him: "These American book matches don't stay lit long enough to start a pipe."

His humor, nevertheless, restored, he points out that "Old Glory" shouldn't be taken too literally, as if everything happened "the way it appears in the book." He has "shaped" the stories, recollecting his conversations with the river-bank dwellers later "in tranquility." Consider it, rather, "an autobiographical novel" structured as the passage of life: Minneapolis is youth. Muscatine, Iowa, is adolescence. St. Louis and Sally are marriage. New Orleans is maturity.

Travel writing, he believes, deserves to have an honored place in literature. "It is possible to see books about journeys have an absolute right to sit alongside realistic novels."

For him, it is particularly important to get a proper American inflection into his writing about this country. "American writers, even John Updike who includes lots of British characters, cannot quite get the British accent." To that end, he jots down random conversations and slang he overhears, very often in a bar, adding musical notes to the words to later recall the pitch of the voice.

In March, he will board a 33-foot Scottish fishing trawler that is being refitted for him, and for the next several months he will explore the coasts of the British Isles. "I'm sick of provincial books about England," where the authors "sit on their a---- and write about the country from inside, about the loss of the British Empire, the collapsing economy."

He hopes to see Britain "from the outside," to visit it as a traveler would "a new port of call. To arrive with your alienated mariner's eyes. It seems enormously exciting." He woke up at 3 one morning with the title: "Foreign Lands."

Meanwhile, he is flying back to London in two hours to a waiting girlfriend (divorced after a brief marriage, he does not contemplate another one) and lessons from a professional sailing master.

"I'm not a complete fool. I'm scared for my life."