Early March might be a tad cool for anyplace but the San Juan, but if you like the cold, you could investigate the Taos area, Rio Grande, Red river, etc. or the Pecos, which might be a tad warmer. If you hit the San Juan you could get by with a 4 wt, or even a 3, but you might get a tussle on the 3 if you get into a 22 inch fish. You could pm Vmabuck about the Pecos area.