Shop a floor plan first. The lay needs to support your intended life style. Spend as much time as possible without a sales rep in various configurations going thru what your daily routine will be. Is the kitchen big enough for your normal meal prep? Does the bathroom fit your needs. Could you go a few days inside the coach and not feel like the walls are closing in if the weather is poor? Is there enough interior storage for your day to day needs?
Both the modern Ford and Workhorse chassis will tow up to 5K lbs without a problem as will a diesel powered coach. The diesel will bring additional amentias that will help make the coach more comfortable both at a CG or going down the road but at a bit higher initial cost for the diesel chassis. If your long range plans include a lot of road time a diesel might be better. Do a test drive in each before making a decision and don't let high fuel prices scare you. The true number is cost per mile and you only need a gain of about 2 MPG from a diesel to offset the pump price difference for gasoline.
2006 Hurricane 31D built on a 2006 Ford F53