Just throwing this out there we use a Nissan Frontier to tow our 21FB @ about 5K loaded. We use a WD hitch and Sumo Springs in place of the OEM bump stops. The truck is rated for 6,100 and tows very nicely, level and smooth. It is the longest wheelbase (crew cab) version, similar to an extended cab 1/2 ton domestic.
The Frontier is pretty much the only truck with a factory roof rack which makes getting the kayaks into the woods a snap, and they may even help cut a swath through the air for less drag on the trailer. Just a guess though.
The real payoff is the narrower track which makes getting through the forest, after the trailer is set up, to the fishing holes. Fold in the mirrors and bushwhack away