Concert Update: Trey Anastasio February 1, 2001 - The Boston Globe (ARTS; Pg. C3) by Steve Morse Phish has taken the year off, but Phish singer/guitarist Trey Anastasio is still headed out on the road. He'll play the Orpheum Theatre on Feb. 21. Tickets are $27.50 and go on sale tomorrow at 10 a.m. David Gray headlines the Orpheum on April 28. Tickets are $26 and on sale Feb. 10 at 10 a.m. Both shows through Ticketmaster. The reunited Waterboys will play an 18-plus show at Avalon March 24. Tickets are $25.25 and on sale Feb. 9 (a day earlier on the Internet, through dlclive.com). Trey funky: Although Phish is on hiatus, the band's singer/guitarist, Trey Anastasio, is not standing pat. He just debuted some new classical music at a concert in his home base of Burlington, Vt., (excerpts to be aired this weekend on ''CBS Sunday Morning'') and he's on the road with a solo tour coming to a sold-out Orpheum on Wednesday. ''It will be up, dance-able, over-the-top, funk-groove horn stuff,'' says Phish manager John Paluska, noting that most of it will be original. The band also features Russ Lawton (drums), Tony Markellis (bass), and a three-member horn section.