The guests paying for the reservation are likely a couple who want a king bed. 

Tenants pay for gas and electric, owner pays for water.

It does require that you pay attention to the funds available in the sub-accounts, but you should be on top of that anyway.Hope this helps!

Building ground up defiantly takes a lot more knowledge vs rehab.

Resulting in us paying this HELOC back slowly for time being.

I took some money out of my 401 K to pay back some debts. 

In terms of your grandfather living there as long as he's not the owner having a dwelling fire/rental property insurance policy is appropriate.As @Greg Scott pointed out he should have a renters insurance policy whether or not he's actually paying rent.In terms of liability coverage, that depends on what you have to protect so there's no one-size fits all approach.

The prospect signs an authorization allowing us to contact the employer to confirm their rate of pay and the duration of their employment.

I have been paying the fee for my tenants so far, but I am now curious whether this charge could be the tenants' responsibility.

Residents often have to travel to Millbury or Northborough to access malls, and many commute eastward for higher-paying jobs.