I really don't think you could build out that harborfreight trailer to run a 16 footer inflated; and even if you did, I'd be scared about which shuttle roads I'd take it on. I also have a thing about protecting the tubes as much from rocks being kicked up, and then you're talking about flaring wood out from the frame pretty far.
I guess it really depends on your budget- I got really lucky and picked up bombproof 10' x 6' flatbed for $325, and added rollers, a winch, new tires & lighting for another $200. Personally, I think that's the minumum size you need for hauling a 16 boat- mine is the Aire 156 and it hangs off a few feet on either end. You also need to consider the length of the tongue, given where the boat sits and what happens when you turn.
My sources for tracking down trailers were:
- Craigslist (obviously)- but check out on the west slope & New Mexico too
- The Thrifty Nickel - especially the west slope. For some reason there are a ton of trailers in Junction. Probably slednecks.
- Northern tool has some nice pre-assembled setups: North Star Trailer Sportstar II ATV Trailer Kit 61in. x 109in. | Trailers | Northern Tool + Equipment
- Build your own- Again, from Northern tool- Utility Trailer Blueprints & Dump Trailer Blueprints : Northern Tool + Equipment or you can an axel there, then go get parts locally and add your own stuff.