For someone who is self managing a portfolio of rentals, any recommendation for bookkeeping books?

It should be telling that not a single person is coming to Clayton's defense.

Self Storage. 

You can absolutely self manage no problem.

But this diversifies from just Self Storage.  

If you DM me, I can send suggestions.Yes, you'll want to record the docs after you execute the transaction.Also, don't self-service the loan.

I plan to self-manage these properties and intend to operate my portfolio as a business, tracking all income and expenses while avoiding the commingling of personal and business funds.

For most loans especially for first time homebuyers, your lender wants to see a 2 year work history of the same job that you are or will be working (same thing if you are self-employed).

Self storage will have different networks and nuances than multifamily or office or retail.  

American IRA is hosting a live session on End-of-Year Considerations for Your Self-Directed IRAs and 401(k)s on December 4th at 12:00 PM.