They sign it and they still sometimes show up and change their mind but I charge them for it.

After running the numbers with all of the expenses and assuming I can charge more in rent on the renovated side, I have determined that it is a good deal and could even have positive cash flow after some more renovations are made to the other side after the tenants move out. 

Even though it prints out on a separate page, I don't charge extra for that.  

I personally don't charge an application fee, because of personal reasons...I screen and then let the selected tenant complete the criminal/credit/background check through an independent party that collects the fee.

Five friends will be high risk for turning into an animal house.If you're this desperate, I would at least charge extra rent per additional person.

So basically the question I have is what can I charge them for us to clean the house? 

Commissions are negotiated and can be more or less depending on your office policy.Or, again with your managing broker's permission, tell the seller you know several investors that might be interested and get a listing... maybe a limited listing instead of a contract to buy it yourself... maybe as a transaction broker so you're just helping the buyer and seller consummate the sale (not representing either party as a fiduciary) and charge a commission instead of a wholesale fee.Just spit-balling ideas for you, but check with your managing broker to structure something that does work for all of you.

I’ve met commercial loan brokers that charge 2% to setup the deal.

It only costed me half the charge by doing digging way instead of tunnel way. 

The reputable RV parks that do allow short term rentals, charge a management fee to manage the site since it is assumed you (the owner) are not going to be there very often.