[tevake]

It could be a win win, you keep the buffer, neighbor gets to have pole barn.
The commercial agreement mentioned could work. Just add their first right to renegotiate at end of lease term.

Try to design the layout so he access from his place to keep his use/ traffic impact to a minimum to your place.

Could cover some annual cost for the place.
Need to figure the additional tax and insurance costs into his lease cost.

Cheers Richard