IF THERE'S one thing Bruce Hornsby doesn't need, it's another job. He just landed one, though. Beginning in September, he'll be on the road with the Grateful Dead, replacing keyboardist Brent Mydland, who died earlier this summer.

"Basically, what it means is that a full plate is now overflowing," says Hornsby, who will bring his own band, the Range, to Wolf Trap Wednesday night. Last summer Hornsby and the Range frequently opened for the Dead and occasionally jammed with them. But as yet, Hornsby has never played a full concert with the band.

"I'm woodshedding now, trying to learn a 100-plus songs," he explains on the phone, in the middle of an extensive tour with his own band. "The Dead are playing five nights at Madison Square Garden in September and then we're going to team up again in Europe. One of my favorite Dead albums is 'Europe '72,' so maybe I'll be on 'Europe '90.' "

In the meantime, the 35-year-old Virginia native, who recently moved back to Williamsburg, isn't likely to get much time off. In addition to touring with the Range and promoting its current album, Hornsby has been busy of late producing a new Leon Russell release, writing material for the Band's reunion album and working in the studio with everyone from Bob Dylan (on his upcoming release "Under the Red Sky") and the Cowboy Junkies (who will open for the Range at Wolf Trap) to Cheap Trick and Edie Brickell.

"For me, that's what it's all about -- working with great musicians and artists . . . . With Dylan, it was really loose and spontaneous, as I guess most people would expect it to be. He taught me one song on the piano and then we just jammed and one of the jams turned into a song. You just go in there and wing it," he says.

Not long ago, Hornsby jammed in the studio with the Nitty Gritty Dirt Band and the experience helped shape "A Night on the Town."

Recalling his work on the Dirt Band's "Will the Circle Be Unbroken, Vol. 2," Hornsby says, "We did this bluegrass version of 'Valley Road' at a breakneck pace and that record captured a certain spark and spontaneity that I never captured on a record before. That's because there were just 10 guys in the studio playing with no overdubs. It was great fun, so when we went to record the new album that's what I was looking for -- that spark and spontaneity. It may seem odd to say this, because they were so successful, but the first two albums were hell to make. This one was a lot of fun."

As a result, "A Night on the Town" marks a sharp departure for the Range. The band's sound took on a harder rock edge, partly because Hornsby's lyrical piano was purposely downplayed. "Anyone with ears can tell that the first two albums were basically solo efforts with a little sprinkling of the band," says Hornsby. "I just thought it was time to show a different side of the band."

Because his other albums did so well, Hornsby concedes it was tempting to repeat himself, to fall into something he calls "one-trick ponyism." But what he really wanted to do was "make the first true Bruce Hornsby and the Range album."

If the sound has changed, the subject matter hasn't. "A Night On the Town" has its share of craftily composed small-town vignettes -- some of them written by by Hornsby and his brother John, a lawyer in Raleigh, N.C. -- and two topical themes Hornsby has dealt with in the past: the environment and racism.

"Barren Ground" was inspired by a dinner conversation Hornsby had with New Jersey Sen. Bill Bradley regarding the Valdez oil spill, while "Fire on the Cross," which is reminiscent of Hornsby's first Top 40 hit "The Way It Is," chronicles a Ku Klux Klan meeting.

"Some people think that the Klan are just part of history, part of the past," says Hornsby, who admits he receives hate mail every now and then. "But I think racism is getting stronger, if anything. That's why we wrote 'Fire on the Cross.' These groups just go under different names -- the skinheads, the White Aryan Resistance, the Order, the Identity -- there's a lot of groups out there now with the same aim. The song is sort of a warning. Things aren't getting better." BRUCE HORNSBY AND THE RANGE --

Appearing Wednesday with Cowboy Junkies at Wolf Trap. Call 432-0200.