Most importantly if she stays and continues to complain don't engage in discussions follow the same policy with everyone and notice her on nonrenewal at leases end.

I would talk to a couple of propane companies regarding policies before you make any decision.

My policy is that I will not hold a vacant unit for more than one week.

You'll need decorative items, creature comforts like books and DVDs, linens and towels (including enough for your longest anticipated stay), bathroom items like shampoo and soap and toilet paper, and a monthly budget for re-supplies of these.I'd also recommend purchasing a vacation rental insurance policy, to cover the furniture items and other things which may get damaged by a guest. 

@Ivan Calais CoelhoMake sure you talk to your insurance company to get a "landlord policy" and max out the liability coverage..typically it's $1mil.

Originally we purchased the property with a policy that was about $900/unit (still bad) - we had to switch due to us changing property mangers while being under their umbrella policy.

Further, are there blanket policies (like an umbrella insurance) where they cover multiple properties at a subsidized price.Seeking wisdom from the forum!

While its been said that the best policy even for wholesalers is to be open and honest, not all wholesalers operate that way. 

Easiest would be to assume the existing policy and then shop around on the backside.

If an animal, enforce your pet policy.