Contracting is a business , the salesman is there to sell a roof to the customer for the most he can get .

We are a custom home builder and can price a new home out much easier than a remodel. 

That usually only applies if you will be bringing customers to your home.

I have customers come into my business and pay by credit card.  

As for his customer service I think there is room for improvement.  

We use QB for accounting and Rent Manager for PM (I often feel like it uses us - although there customer service reps are great).

Without an agreement: the Buyer is your customer and the seller becomes your client because they are the one paying the commission. 

I've looked into Guesty (which seems too expensive for what I hear to be awful customer service), Hostaway, Owner Rez, and Lodgify.

And then when the distributions got paused tell the same customers, who really needed those funds for retirement, they were being short-sighted to focus on de minimis cash flow and should wait for the real money to come in via appreciation?

These are very personal decisions.I can't tell you how many times I had a seller pay me to go in and redo kitchens and baths, and then get called back by the new buyer to redo the brand new custom work....just because of color.I would just put the house on the market and price it a little high, maybe $20k...?