Should be easy since roof line is so close.

We added value by repainting interior, new floors, new roof, resurfaced the pool, added a fence for privacy, upgraded the landscaping, sealed and painted the exterior, added central A/C with new unit, upgraded the irrigation system, added gutters, added security cameras, added hurricane proof front and rear doors.

After one summer of STRs I came back in the winter took a first lean mortgage on the property to replace the roof (and build my RV which I plan on living in while renting in the summer).

Lastly, is it possible to put a “seal” on a current shingled roof, should there be any leaks?

She only did maintenance, but did replace the roof and AC condenser after the fires in 2016 (insurance paid).

To make things even more complicated, I could possibly have roof issues, which means more $$ spent that I won't earn.

This is not only to make sure that people are taking care of the property, but this is also to make sure that tenants aren't overlooking issues that could be addressed now that cost way more later.These can be minor roof leaks, gutter leaks, mostly to do with water penetration.

To me that seems very steep.

The roof was replaced this year and the Central Heat and Air unit was replaced within the last 3 years. 

You just need to shop around more and take care of the big items, like the roof, if needed.