so... clean-out and demo? 

You'll likely want someone that can handle A to Z with marketing, pricing, cleaning, maintanence, decor, websites, reviews etc.

Guests cover the cleaning cost.

Years go by and eventually Grandpa gets tired of fixing porches, nailing gutters and steam cleaning carpets that 'have a couple more years in them. 

deep clean, moisture barrier in crawl space, maintenance to HVAC What was the outcome?

This ensures a clean transition of ownership and responsibility for insurance purposes.

And your cleaners will need to clean out the fireplace ashes each time, make sure the damper is closed, bring wood in or have a pile near the door, whatever.  

It would be wise to rectify it before transfer of title so your starting off clean and hopefully won't have any issues when you go to sell down the road. 

Then there’s city regulations—some places heavily restrict short-term rentals, so you’ve got to check the rules.If you find the right spot and automate stuff (guest communication, cleaning, etc.), it can be profitable.

Very good resource for getting set up with STR property managers, cleaning services, realtors, lenders, etc. https://www.getchalet.com/