I just recently sent this to design-engine in a PM response, but it may help here as well.
He asked about trailer and a tire changing solution:
Well, the easy one is get the NoMar tire changer with the hitch mount. If you do that, when you call, tell Steve that I sent you and he might have a special deal for you. Tell him you race with me.
For the trailers, best place to shop and get an idea of pricing is racingjunk.com, start at http://www.racingjunk.com/category/1..._Trailers.html
and you will find a great understanding for pricing and what is available in the market.
If you want a nice trailer, twin axle, torsion, ramp door is the way to go. there are TONS of great used ones available on the market, and you should be able to get a real steal. Traditionally, barn door trailers are for utility folk, like yard men, laborers, etc.. and as such, the used ones are crap. BUT... you can get them really cheap.
Depending on your budget, that determines what you get. I would stay away from no name trailers, they are total crap. Haulmark, Classic, Pace, etc.. are the ones that you get good value from.
For setting it up, this might help on some of the options: http://web.mac.com/brianwink/iWeb/Travel/Trailers.html
although I'd recommend PitBull restraints for the bike these days.