I think you're best bet for private money is going to be to network at the meetups (Red Stick REI, RING) and on FB/here.

I doubt you'll make 11% with the S&P, but it is probably still your best bet.

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 ...

Depending where your rental is in Chicago, you should also be flexible with your requirements.

Long-term planning allows for steady growth, compounding returns, and the flexibility to adapt to economic and societal changes.

(I know a lot of investors who are doing this, but I've been surprised to find out that it's a new concept that others haven't considered.)The more units, the better in this scenario because you can hedge your bets with more units.

I can bet if inflation runs then Boston prices skyrocket, but I doubt Austin does.

Since you're selling the business and real estate to a partner/friend you will have some flexibility in value determination. 

Their clear incentive is to bet on falling interest rates between now and debt maturity.A small handful of owners are forced to sell due to a looming balloon payment that a refi won't cover, but you're not going to find one of those by driving the market when any commercial broker can just look up properties on that basis and start making calls. 

Find one that can be custom to your needs, has flexible pricing, no long-term, high-cost memberships and excellent customer services to determine how to best market to your leads.