Without being a cash buyer and the market being crazy makes the 70% rule seem almost impossible.

It's done all the time you need to know the lending rules for your state.  

The general rule is that a veteran may have only one outstanding VA loan at a time.   

If it was easy...

@Carlos CoronadoHey Carlos - welcome -A cash buyer is easy to find if you have the property ....

So the first stages of looking up ownership/investors and writing letters to both parties seems easy enough, but I'm curious what this contract deal seems to look like.

You'll either want to create a partnership agreement or form an LLC and create an operating agreement, which will incapsulate both of your rules, responsibilities, rights and terms of the agreement.

These are not particularly onerous, and, quite frankly, are probably a good rule of thumb to follow.  

The billboard company has 6 years left on their lease and as with any major billboard company they have an easy out in the lease(90 days).

PROACTIVELY Structure the deal.HOLD the property, refi and take out cash repeatedly if you need it and current lending rules allow ( that option cycles about every 5 years!)