The trailer has to be opened up to allow for access to the tires. On ours, which is a 97, you unscrew the "skirts" on the outside of the wheelwells. Of course, you have to jack up the TM (placing the jack under the frame). The newer ones have scissor jacks that would probably assist with this procedure, but we had to use a bottle jack.
We had the pleasure of doing this alongside a busy freeway at a spot on the road where the tire that had to be changed was way below the road grade. It was not fun. We now have roadside RV assistance insurance (and 3 new tires).
