So far I've been relieved to own them in cash because the first 12-16 months I had to fix/replace/upgrade a lot of things that the previous landlord(s) neglected as well as deal with some bad inherited tenants.

Learn as much as you can, like you appear to be doing, but do not allow learning to replace moving forward. 

Inspection found failed septic system ($15k replacement) which seller paid for. 

Two things to think about:There always something that needs replacing / repair when you buy a new property.

They have replaced all their cars with EV and now asking me if they can also get Solar panels installed.

When we replaced the roof/decking we ended up needing to replace about $2k worth of trim that was hidden under the first roof.

The house is old as well, with some issues (all 3 furnaces will need to be replaced within 3-5 years).What would be the wisest choice for a first investment?

You can find a more thorough SEO strategy here (link in original article).Post consistent videos on YouTube — YouTube is the second most-used online search engine right behind Google.

@Ronald Daley - you mean a structural engineer?

Reverse engineer your search for investors by being valuable to them by giving content that benefits them.2.