So I offered to pay for the flight, if they returned a clean and empty house.

The tenants have paid and if someone is thinking about moving out then an extra surcharge that hits if they aren't out in time for us to turn the place for a lucrative AirBNB short term rental can help massage the move out timing.That said with MTR we do not have the cleaning costs that eat up a lot of STR gross, and its lower hassle in some ways.  

Few left were broken, never cleaned.

@Andrew Grimmett If a seller is hesitant due to capital gains taxes, consider creative solutions: suggest an installment sale (seller financing) to spread tax liability over time, a 1031 exchange to defer taxes by reinvesting in another property, or a structured sale for flexible deferred payments.

I've seen many responses from contractors, saying they've got to buy materials, pay their workers, etc and if they don't know you, you should expect to pay a deposit.I can see both sides of the problem.Contractors, if I foot the bill for the materials, your risk is lessened.How can I propose a fair solution to my contractors?

Pic 36, metal under rooftop needs cleaning, storm cellar (?)

Build a local team for cleaning and repairs to streamline operations.

More like  2X to 5X the cash out.. these are done with builder developers on their deals So put out 300k get 300k back in profit plus the interest rate. most small builders/ developers need to have a equity partner so you just do both you lend the money and are the equity partner.. pretty clean..

We have not disabled ours or converted to gas, but Tenant must sign a Fireplace Addendum stating if they use it, we require a higher renter's liability policy with us as additional insured, rules on wood, storage, use, safety, they pay for yearly professional cleaning each year they are there, etc.  

Likely your best solution is to do a 1031 exchange.