I also read in real estate by the numbers that it's risky to bet on market appreciation.

I could maybe sign up with that theory if the GPs were using the side hustle money as a way of cutting or eliminating their fees & salaries altogether while they try to hang in long enough to hope for enough rate cuts to refinance or the market to unfreeze and let them unload at least at break-even, but I bet none of them do anything of the kind. 

My son just joined the Navy and now that I’m an empty nester I want to make a shift and bet on myself!

Fortunately, you will be able to to a 1033 exchange into new property and avoid any tax on the gain. 

You might explore partnerships where you fund all-cash deals in exchange for a portion of the profit.

Now, I think the best exit strategy to avoid recapture tax continue to build on your portfolio would be to do a 1031 exchange. 

The LLC has to do the 1031 exchange because that is the tax return reporting the activity of the property. 

In exchange for a reasonable discount of course. 

For context, 4 adults and all our tech living here, we were running about $250/mo on average per month for electricity anyway... outside of summer a/c useage. so all in all, its saved me about $2k a year if i had to guesstimate for you (it stays hot here through October usually).i still owe about $23k on mine, have no intentions of selling the house. but if i decide to move out and rent the whole house out, our market would support higher rent in exchange for no electricity bill. i think you just need to decide what YOUR main benefit of having the panels are. for me it was for the house-hack, and consistent billing, despite the usage. if its strictly for property value increase, i'm not sure it would be worth it, pending your specific market. 

It sounds like they have money, and it sounds like in exchange for that money you're setting them up with an income stream.