Commercial land with billboards.. questions to ask

[Eric P.]

A gentleman not far from where I live is looking to unload 4 acres of commercial land through a private sale.  Its on a busy rd, growing area, and currently has 3 billboards that generate "$20,000 a year".  I'm very interested for a few reasons.

1) Its local for me and from what I can see compared to other land in the area is a very good price

2) The seller is not against doing seller financing which I'd likely take advantage of

3) he's willing to do a partial trade for some high end "toys" I own (sports car, motorcycles, etc.)

Before going any further I'll be researching the township's rules and regulations on billboards to get a better understanding.  They are all currently leased so I'll also want to see a copy of the lease agreement to be sure there isn't some weird clauses about a change in ownership.  The other reason I like this property is because it has always been my dream to one day own a Self Storage facility.  This could get me closer to that dream as I could possibly develop the land a few years down the line.

Wondering if there are certain things I should focus on, questions I should ask, etc. I'll likely make the purchase through my LLC should I go through with it.