I'm staying in one outside of Asheville right now and I'm in love with the concept and really considering it on my 45 Acre plot of land  

I own the land and it is valued at $150k. 

The appraisal would not be of the treehouse persay, but of the land and everything attached to it. 

If not, the way you build trust is to take a step back and gain some experience investing first in some way shape or form.Then you want to assemble a team who have the experience in all the aspects needed to make the proposed project successful.

This particular tract of land is a fairly rectangular 7 acres (400'x700', more than needed) and is owned by someone who stopped using it prob 10 years ago.

They are in no way shape or form designed to be helpful to the average real estate investor or business owner. 

I have a middle aged guy with a disabled son (wheelchair) who wants to move in our unit. Rent is 1900 and his gross monthly is 4000. He does have 100k in the bank. Would you consider this remnant? I’m in Melbourne FL ...

When i started in the mid 70s I only sold land and land commish in those days was 10%  .. most of the deals I took on were ones that other agents simply could not sell as they were very rural props in N.

I'm searching for a plot of land to build Treehouses for Airbnb. 

Not to say you can’t do multiple of those with one strategy, but answering that for yourself will help you land on LTR/MTR/STR etc.