The specs listed are generic, need to look at the weight label from the factory, usually located in driver door flange to see what payload your F-150 has. That should give you a starting point, ultimately going to some scales loaded with all the passengers and stuff you intend to have when towing will account for actual remaining payload. Most will run out of payload well before truck's trailer towing capacity is exceeded.
Virtually every brand will have floorplans to accommodate your needs, might have to remove or reorient some of the furniture to have two separate work stations. Grand Design is a quality manufacturer known for backing their products under warranty, try a smaller, lighter floorplan. And finally, possibly consider a slightly used unit, maybe a couple of years old to save considerable money off new. Saves the hassle since most have had all their warranty issues resolved.
