His legal advice saved the deal, because if I was left to my own remedies of "good faith" negotiations, I would have played all my cards and been forced to fold.

I have about 150k cash to play with.

I'll play with Rentometer over the next few days and see how far it gets me.I was finding City-Data was cutting off in 2010 ish depending on the area. 

You would need to network with HR professionals in your market for referrals since they generally are the ones who arrange for those contracts.Do your homework...it would not be the play I would make.

The more systems you have in play, the quicker you can assess and make decisions.

Househacking here isn't an income play; it's a wealth-building play.

Also keep in mind depreciation plays into this, which you don't mention at all. 

I think you are playing in a dangerous situation if you go the hard money route.I also want to help give you realistic expectations.

If he has been doing it his way for almost 50 years there is a good chance he isn’t going to was to hear it frankly.That said, if you play along, even if you can’t use subtle techniques to move things along, you may win his trust and be given some buildings to manage- after which you can slowly change things.Above all else enjoy your time with him.

This will avoid issues down the road if she is flaky and using boyfriend to play the tenant game.