I am under contract on a flip that is not in my area so I will be hiring a GC to manage the renovation on this project. 

Hi Ken, I am a broker here in California and I manage over 100 STR properties.

STR is a strategy and an investment (furnishings, learning to self-manage, hiring cleaners, etc.)

They have a handy feature where you can manage multiple accounts for each of your properties but only need to remember one login.

I plan on hiring a general contractor ( like many do) and then hiring my property manager to manage him. 

It seems to be a very tightly managed building, which is typical for Ocean City, Maryland from what I have heard from my real estate agent and lender.

Since I will be leaving my corporate job and effectively self-employed as I manage most of my MF portfolio, can I roll my retirement savings into a Solo 401k and invest in RE with the money?

My PM company does manage some there though.  

It's saturated now and management fees are high for STR, up to 25 percent.

Could you self manage?