They pay $600 for the tent because they don't want to leave the party. 

But probably not that high.The IRS has shown some comfort level with sales to related parties as long as the following happens:1.

If they are together then you need to figure how you work with the two rentals to pay the water bill or pay it yourself.4) You will need to work out how mail is delivered for two parties at one address. 

This is true even if the claim is not your fault, which is why people who get into car accidents where the other party was 100% at fault frequently see their auto insurance premiums go up.

The owner had passed away and the children wanted to sell it, we negotiated down the asking price and both parties were happy.

I would not rely on either party telling you the property is a good "deal."

Would it have to be vacant at close or could the agreement extend an additional 59 days after close as long as there is a signed document by all parties?

For the deal to be win-win, both parties need to be protected, so it is best to do this right from the outset.

It is like having a “3rd party verification” showing you are not pulling numbers out of the air.Lastly, I try not to have my leases expire in the months of Nov through Feb.

Tracking vacancy dollars is important, particularly when using 3rd party management.You can categorize turnover costs in a Turnover P&L account this is separate from ongoing Repairs.