Then there's the occasion when you run across that individual who is determined to manipulate the system so they can cause you as much grief and cost you as much money as possible.

I recommend you leave them your contact information and continue to follow up on occasion.

However, I have used TSP loans on three occasions to purchase real estate.

@Brandon Turner and @David Greene have mentioned on several occasions that "rockstars hangout with rockstars."  

I have also dealt with the City of Columbia on several occasions regarding the conformity of MFH with a long vacancy.

Although we will likely not use the property ourselves as we are in California, my partner, who lives on the east coast does plan to use it on occasion for vacation from time to time. 

Only one I’ve seen break out a ladder and get into the attic space on multiple occasions.

i see two options here 1) you can go back to dad and break it down as hey i cant close on the house until it's vacant and see if he can help in getting them out, 2) offer some moving expense if the lot is really that desirable to you I know not what you want to hear as the investor but it has worked on numerous occasions, 3) you will have to take it to the courts as final resolution so the sheriff can remove them.

> I've been renting out his house for a number of years, to help pay his assisted-living costs;y'all have helped me with that on a couple of occasions! 

Aside from that rare occasion, the longest I've gone without a tenant is about 3 weeks.