I wrote up a blog on how I did ours in case anyone needed ideas. No gen prep, so rigged up a manual transfer switch and a cord that drops down through the bottom of the passenger side propane compartment, long enough to reach the truck bed. Easy hookup to the Honda gens in the truck bed when making a rest stop or a one-night boondock. We also use this cord (along with a 30 amp extension cord) when the electric service is in a weird spot and only need 30 amps.
http://manualtranferswitch.blogspot.com/