Picked up a single wheel trailer to use as my platform fer a boat tail...fer $100! Still had to add lights, new rim/tire, safety chains, new deck and fasteners, tags and registration, and anti-rattle devices...so my investment is just under $300.
The rear wheel swivels similar to a shopping cart wheel. I should be able to close up the gap fairly easily between the truck bed and the boat tail trailer.
I'm gonna keep the cargo body on there fer now until I git some numbers. I will probably transition to extra body panels to smooth the transitions from the truck to the boat tail fer awhile and then eventually remove the cargo body to go with a custom setup.