Damage, excessive noise and $100 per head over max occupancy.

The answer varies greatly depending on the arrangement of your deal with the owner/landlord but in general you need renters insurance to cover your contents (since you are renter presumably) and then excess liability coverage for your short term rental activities.

After determining and correcting the source of the excess moisture paint using a coat of Killz in that room as a primer. 

It doesn't have to be 100% but even 20,30,50% can give you excess cash to continue investing. 

She can’t make excessive noise or be aggressive.

If using accurate underwriting (something close to 50% expense estimate) your costs will be far in excess of your $3k current lodging expense.  

I hav some excess cash that I would like to put in a rental property.

Additionally, explore markets with low vacancy rates and increasing rents, reflecting a strong appetite for rental properties.

A tenant who wants to stay and is on a fixed income is likely to stay a long time which means you won't have excess loss to vacancy/turnover.

In my area the water company will forgive excess usage if it can verify there was a temporary water leak causing it.