Thanks for the info, guys!
While the trailer steer axle has enough caster on it to make it self-turning, like fuzzy says the axle AND probably the tierod needs to be cut out to clear the driveshaft. Don't know how cutting and reassembly will work, exactly.
fuzzy- can you keep me updated on how your setup works?
Here's a pic I found; anybody know the size of the tube used, and thickness of the arch?
Brian's idea of using a steer axle might work, if the axle has enough caster in it to self-turn. Got any pics of this setup Brian?