In downtown Thurmont, Maryland, a few miles from the Camp David presidential retreat, church bells peal the noon hour with hymns to deserted streets. Everyone has gone inside to escape the heat, except for a calico cat that pauses sullenly in the middle of Main Street, then sulks from a car's path.

In the Cozy Restaurant a few blocks from Main, display cases chronicle recent local excitement. Last year, the Catoctin High School Cougars won the MVAL Region II championship; they all signed the basketball. Newspaper clippings from September 1978 recall the Camp David Accords: "Summit Makes Small Maryland Town a National Star; David Brinkley, Barbara Walters on Main Street."

Margaret Bruchey, who has been town librarian for the past 20 years, remembers it well: "The reporters couldn't go into Camp David and kept bothering me. I just kept saying nothing ever happened here in Thurmont. And it doesn't. That's why I live here."

For the out-of-town visitor, however, this quaint town and its rural surroundings offer a number of interesting sights: orchards and roadside stands, an old ironworks, three covered bridges, Catoctin Mountain National Park with its nature trails and wildlife, and Cunningham Falls State Park, with a waterfall and a lake.

Although Bruchey's favorite place in town is right there at the checkout desk of the Thurmont Library, she acknowledges the local draws of fishing, camping and the Reagan recreation of horseback riding. "I go up and sit by the creek and put my feet in the water every now and then," she said, referring to Hunting Creek, where President Jimmy Carter used to fish.

Like any other small town, Thurmont has antique shops, a sporting goods store with "WORMS," little taverns and old historic churches like APPLES CHURCH. Take Main Street east, turn left on Apples Church Road, and look to the right to see the church, built in 1826. Take Main Street (Route 77) west, and you'll pass between two stone houses at the intersection with Altamont Avenue. Both were built in the early 1800s by Jacob Weller; the larger one on the right was the town's first tavern. The one across the street with the pale green eaves is known locally as the MATCH HOUSE, where in 1825 Weller mell. In 1942, President Franklin D. Roosevelt chose "Camp Hi-Catoctin" as a secret retreat and renamed it "Shangri-La." In 1953, President Eisenhower renamed it Camp David after his grandson. About midway between the visitors' center and Camp David winds the CHARCOAL TRAIL, which gives a glimpse into some of the former commerce of the Thurmont area. For over a hundred years, starting in 1774, woodchoppers and colliers worked on the slopes of Catoctin Mountain to make charcoal for the CATOCTIN IRON FURNACE a few miles away. The cutters cleared the trees from the land, then moved on to another stand; they'd return 25 years later to harvest new growth. The collier -- who burned the wood to make charcoal -- slept in a hut near the hearth. A stack took two weeks to burn, and every three hours he had to go out and jump on it to settle the charred wood. Festooned with cobwebs, a reconstructed collier's hut may be seen; the fireplace is original. Catoctin Furnace can be seen on Route 806, just off U.S. 15, about four miles south of Thurmont. It furnished shells for the Battle of Yorktown and manufactured pots, kettles and stoves. The three remaining covered bridges in Frederick County are nearby. To reach LOY'S BRIDGE from Thurmont, take Route 77 (where it's called Rocky Ridge Road) east about three miles to the intersection with Creagerstown Road. Turn right and drive half a mile to the bridge. UTICA MILLS BRIDGE is about 11 miles south of Thurmont: Follow U.S. 15 and turn left on Old Frederick Road. Take Old Frederick Road to Utica Road, and turn left to the bridge. To reach the RODDY ROAD BRIDGE from Thurmont, take U.S. 15 north about a mile and turn right onto Roddy Road.

Out U.S. 15, just past the turnoff for Roddy Road, is the SHAMROCK RESTAURANT (''Git stuft with our stuft haddock'') and Blarney Room Lounge. Owner Mike Fitzgerald can be found here seven days a week. The restaurant was a dancehall before he bought it 20 years ago, but now it serves steaks, crabcakes and country ham.

Fitzgerald's favorite scenic drive skirts a panorama of orchards and rolling farmland, where, if it's not too hazy, ''You can see clear to Union Bridge,'' he said. Take U.S. 15 from Thurmont; turn left at the Catoctin Orchard stand. Keep right on Orchard Road to Kelbaugh. Turn left on Black Road for a mountain vista, or continue on Kelbaugh for a lower-story view. Turn left at the end of Kelbaugh and continue another quarter- mile to the entrance of the National Catholic Shrine's replica of the GROTTO OF LOURDES. The overlook from the parking lot is a good one, and the garden path to the grotto is a cool, shaded walk. The other afternoon, Fitzgerald lamented the disintegration of barns -- "Barns that are here today, when they're gone, that's the end of it." There are some that are all brick, and some, called bank barns, are built into sloping ground and can be entered from both floors.

But much remains of old country life around Camp David and Thurmont, where chickory, Queen Anne's lace and black-eyed susans bob beside the road, where deer can be spotted in daylight, and where sweet corn is advertised for $1.40 a dozen and chicken- and-ham dinners last "from noon til . . ."