In your case, it sounds like a similar story.. you identified a property with potential, tackled the structural work, and brought it back to life in a way that justifies a higher price.

They are my favorite, because they are cheap and snap together higher, which better protects from splashing water.

If they have trouble with making rental payments, they need to start improving their skills and look for a higher paying job or double down and get two jobs.

For "seller" now there is an incentive for lower cash-flow, and a penalty for improvement of a higher cash-flow. 

Figure rates are significantly higher doing this instead of the more straight forward approach.  

Another option if you're looking for something with higher yield than index funds, that's hands off, and will teach you a lot about real estate investing without having to do it yourself could be investing in syndications which is referred to in the book Jonathan recommended.

My first question is do I pick a good, better, best system that costs from less to more $$ and do I justify the more expensive energy efficient system to grab a little higher rents since tenants will save money.

The income is much higher but it does come with a more management.

The higher interest rates make it that much harder. 

They beat my existing premium by over 30% without sacrificing coverage (I did choose a slightly higher deductible though to get some extra savings here).