it rolls now!
started with a freebie pop-up camper with a family of mice in it, stripped it all down to bare frame, and made a "subframe" which the entire suspension assembly bolts to, which in turn bolts to the frame of the pop-up.
well, here are the plans


suspension started with cutting/pressing out the dead spindles from a junkyard chevy s10. cheap and strong and reliable!

then i turned some 'adapter sleeves' to press the spindles into, and then 'adapt' to a more convenient OD to slip into a standard tube.

and then welded up a subframe and control arms


and look, assemblage

aand now it rolls on its own wheels


need to turn some spacers and then i can bolt on the shocks, leftovers from a previous project

and then i can start the woodwork.
but im juggling several projects so who knows when this might progress next

If you put your mind to it you might be able to have disc brakes with a surge coupler.