The concern I have is that he will not be available to sign and they left some clothes and other random low value items behind.

Here is an example from our property rules:APPLIANCES.Appliances included in the rental of the premises, as noted in the rental agreement, such as a refrigerator, range, dishwasher, clothes washer or clothes dryer, belong to Landlord.If Tenant wishes to use these appliances, Tenant agrees to use them properly in accordance with manufacturer instructions and assumes all responsibility for their care and cleaning.In the event there is a malfunction of an appliance or an appliance is in need of repair, Tenant agrees to notify Landlord in a timely manner and in writing.If Tenant wishes to use their own appliances, Tenant agrees to contact Landlord in advance to obtain prior written approval and instructions, as the removal and installation of appliances must be done with care to prevent damage to the appliance and/or building.Relying on text messages for official communications is not a good way to go.

(Invision yourself standing there just out of the shower drying your hair and breaker(or gfi) trips and your standing there without clothes on in the DARK,,,and how you would fix that???) 

Currently he keeps complaining about being able to see their clothes hanging in the window (telling me to tell the tenants to keep the blinds shut) and empty beer bottles on the deck occasionally.

Explain it to her like this $250 over the course of a year is $3,000, which can be a nice vacation, watch, clothes, dining out etc.

Don't buy expensive clothes, cars, newest cell phone, etc.

You can do some damping on the door slams etc, but otherwise I wouldn't go beyond that.....This isn't loud music or parties or kids running around at unreasonable times...these are normal noises that life makes....one tenant just doesn't like them at a certain time.

If you haven’t worn clothes in six months get rid of them.

Lets say they loose their belongings (furniture, clothing, electronics, kitchen wares, etc.) there would be coverage for them to be made whole.Good job requiring your tenants to have renter's insurance - it's as beneficial to them as it is to you as the investor! 

It takes a buttload of time, effort, and money to clean that up, and it doesn't just go away after a couple weeks - somebody has to scrub that crap off the walls, floors, cabinets, vents, curtains, furniture, clothes - literally EVERYTHING.