That’s the very simplified version but raising capital is always your biggest limiting factor so the more investors you can connect with the better. 

I have 21 units and have recently formed a Series LLC for all 21 units. That has gone smoothly with the exception of one unit that I have my disabled brother living in. I have placed 50% ownership of that one unit in ...

I bet it looks very amateurish.

If your goal is to offset your mortgage with a house hack then Lowell would be a good bet, but if you're looking for a longer term appreciation play then the areas closer to the city would be better, although the offset from cashflow may be lower than what you're looking for.A good step for you would be to dig into specific areas more as @Lien Vuong noted above.

If you don't want the headache of management that is fine but will limit your options. 

They are good for comparison of different assets and limited in telling you when, where, or how to invest.

Hey @Mike Pepperday, AirBNB and VRBO are your best bet to see what kind of demand there is for STRs in general.

Some investors like having each property in its own LLC to limit risk, like if something happens with one property, it doesn’t affect the others.That said, managing multiple LLCs can be a hassle and add costs, especially with only a few doors.

Personally I’d do a 1031 to save $40k, I’d skip the LLC, increase the limit on my umbrella, and call it a day.

Best bet is likely (not absolute - everyone's situation is different) is to look at a national lender or broker that has options in lots of states - its a great development versus 20 odd years ago, with technology, internet, places like this - can have access to many more options than before (local broker or lender thats it)