With yaks, I would take a serious look at New River or Shenandoah River. Shoot, with a week, you could fish both! ... Check out www.lowwaterbridgecampground.com in Bentonville, VA. Pretty nice campground right on Shenandoah River... Have had 100 fish days in that area from a canoe. Have caught smallies 3+ there, too.
As for New River, I hear May can be really good fishing. The New holds some huge smallies! Can't give you a whole lot of info about where to go though. Sorry...
Good luck with your trip! Sounds like it will be a fun week!