I've been through several rainy trips on the chattooga river in the last few years (not surprising since the area gets 80"+ a year). I'd have to emphasize bringing a tarp or 2. Really nice to be able to be out of the tent in the rain, even if you're stuck under a tarp.

The other thing is to make sure the water repellant on your raingear is performing well (not the laminate, the coating on the fabric that makes water bead off). Doesn't matter how well your shell breathes, if the fabric wets out you'll get soaked from sweat. There's plenty of them out there, but the ReviveX spray that I've used seems to work very well.