I feel you on the tiny house "love".
Especially when people spend thousands on them, I mean what's the point?
About the 5th wheel,rather than fix the roof, you could build an open sided shop high enough to park the 5th wheel under it.
Clear plastic sheeting could close in the sides creating solar gain in the winter, and a wood burner could share that space, w/out being inside of the 5 wheel.
It occurs to me that that brush could be Hugeled, or made into a dead hedge,perhaps even made into charcoal.
Looks like you could have a great spot for AgroForestry, running animals under and around the trees.
How is the deer population? I can imagine a nice smokehouse right next to a processing hut...