FJ, I've been contemplating this same problem for some time now in the eventuality that I move to CO. My thought is to get a 4x4 from the local DIY center, cut it to length (so that it's a good snug fit into the front of the trailer), and mount Eye-bolts through it close to the ends. To help matters, I'd probably bolt a couple short 2x4's to it in the middle to form a channel for the tire to rest in, and then run tie-down straps from the eye-bolts to the forks, just like if you were hauling it in a pickup. I would think this would be sufficient, and you could even do the same thing in the rear of the trailer for the back end. It really peeved me off when I found out you can only rent their bike trailers locally, what a bunch of unprintable words came out of my mouth!!! I thought about tying off to the wooden side rails, but just don't think they've got enough of an anchor to be sound, so that's why I started thinking about building a "rack" inside the trailer (or truck in my case). I can draw up a sketch and e-mail it to you on Wed (I have a PDF scanner at work) if you're not sure what I'm talking about....
