Good for you for getting started, reading, and saving money for your first investment.STR is a great strategy that can have major upsidesBut this is more like a "business" than an investment.

I had a few that ended up wanting to come a little earlier or a little later, so it ended up being longer than an hour.

I was ambivalent about selling it, even though I live in Wisconsin and am completely reliant on the manager, but a long term tenant moved out and the rehab on the place was exhausting and confusing.   

A newer property in very good condition will require less per month NOW, than an older property that has been milked dry by a prior owner.

The seller may accept an all cash offer below their asking price rather than an offer tied to a mortgage at full price, knowing that the buyer will be able to close and close quickly.

We have umbrella insurance also.Your question is impossible for anyone to answer other than an insurance agent/broker who has your property's current inspection reports IN HAND.  

If it less than an hour each time, then I would agree, $25/visit sounds reasonable. 

He was bored and mentally exhausted.

This is significantly more than an ADU.

-The approval means of conventional and even home equity loans is exhaustive and burdensome.