When a tax-exempt entity such as an IRA engages in a trade or business on a regular or repeated basis, however, then there are taxes that apply (UBIT) meant to protect tax-paying businesses from unfair competition.So, rental property in an IRA should be fully tax-sheltered. 

I am gonna tell everyone I know about a deadbeat and everyone knows everyone in the trades. a contractor who can't front a few hundred in materials or have accounts at the lumber yard probably isn't someone I want to deal with anyway.

I would like to focus on rentals & flips, but I am open to learning all tricks of the trade as well. 

Some alternatives are 1031ing into paper such as a Delaware Statutory Trust (DST), REIT or TIC but personally I would recommend against those because we might be looking at a trade war induced recession. 

in Georgia, the homeowner can pull their own permits.I understand wanting to learn under a GC, HOWEVERI highly recommend that for your own properties, hire individual contractors or handymen, that are the best in trade.

The trade-off I haven't seen discussed in this thread is the questionable upside potential of markets such as Pueblo, Indianapolis and similar ones where the 1% rent ratio is easily surpassed. 

Life companies rarely "re-trade" on loans.

So I am going with the $20-$30 key lock box (and a back up somewhere else in case of an emergency).  

If I sell and do a 1031 I am either trading out here in Denver or going somewhere else.

In my area, you have to talk to the post office as well as the fire department/emergency management.