two boats?
for boat #1, you should consider a full on (or nearly so) whitewater boat (aka “banana” boat).
I’ve not been looking for such, but am aware of the Millbrook lineup. Also check Mad River’s Outrage, Hemlock’s Shaman, Wenonah’s new Recon, Esquif’s lineup, etc.
for boat #2, I’d not look much further than a Rapidfire personally.
Apparently there exists such a thing as a flatwater kayak.
Two boats???
I don’t think that you need two boats. I had an old J boat for a short period of time that could easily handle quickwater and EASY class I.
http://outdoors.webshots.com/photo/2725739280075003331CGXRMr
In fact, the only way I could turn that boat was to stick one end in an eddy and the other in the current. It actually surfed pretty well in SMALL waves. Whatever you choose for your lake tripping boat you could use on the river, unless you are concerned about the occasional scratch.