And with a new roof and ac that decreases Capex for a while too!

However, now with $50k gift of equity + $200k to my grandfather, he noticed that the purchase price increased from the agreed upon $200k to $250k and my grandfather is afraid he will have to pay more taxes due to a higher purchase price.

Typically if you give a long notice (and not over the winter) you can work something out with your landlord where it's not as bad as the lease might stipulate. 

After walk through, I believe my best option is to give a 60 day notice upon closing.

@Ben Bushkuhl    I send a notice out to take the AC out. 

Current tenants were given proper legal notice and would be out by 10/5, so the house would be ready to close on 10/8.

I found a really good contractor on short notice, must've gotten lucky

These same thermostats also have an auto temperature decrease function which brings the heat down to 68 degrees if the thermostat is not touched for 3 hours.

The couple noticed me and beckoned me over to there driveway and I thought " Yep, it's one of those nights!"

Give them written notice that their stuff must be removed by midnight on [DATE].