She pays the rent on time but is generally difficult to deal with. 

I would so similar, say we have had it inspected but if you wish to engage a structural engineer at your expense which will run $2k-$5k you can, and if they find the home uninhabitable we will pay but only in cases where the home is deemed uninhabitable and condemned by the city.

If you've been living in the property for 5 years, you won't have to pay capital gains taxes as well. 

Obviously you want to pay attention to your interest rates, cost of appraisals, and fees for refinancing.

I keep telling him that we’ll need to jump on something once the flip is done otherwise we’ll be paying more in taxes. 

If you are house hacking to have someone else pay your mortgage what would be the point of a separate account if you are just going to switch it over to your checking or directly into your mortgage. 

Vacation homes you do really need to pay attention to the days rented as Yonah said.

There were on sale and I didn't have to pay for sales tax in Portland OR.

Have you been aggressively paying down your mortgage while you are in there to earn even more equity over the longer term? 

Maybe you could hook up with one of these battered women groups, and turn the place into a shelter for battered women, Where the charity would pay for all of the rooms and just use them as needed.