I am starting out in REI, but I have a hard time imagining not maxing out retirement accounts available to me (403b, Roth IRA, etc). 

Strongly suggest you to use the BiggerPockets Calculator as well as look into Lease Options as that might be another exit strategy to save on the repair, hoa, property manager costs. 

He's a smart business owner who "retired" a couple years ago and is now starting new ventures.

So the listing agent may have some extra commission if there is no buyers agent saving the seller money if they are willing to take less to sell directly to a buyer.If the listing agent goes “dual agent” representing both sides.

No savings, so I would finance the investment 100% (use my HELOC for downpayment + mortgage loan for the remaining balance).

Hey guys, I am a new real estate investor and I am trying to save money in every way during our second deal, first rehab.

BTW, after retirement, I worked at a senior center, and helped members apply for apartments.

Goals will help with saving, investing, and keep you focused for what you want to accomplish.  

My current goal is to build my portfolio over the next three years before I retire from the military. 

I have my real estate salesperson license, but have only done deals for myself to save the commission.I have decided to dive in head first and focus on real estate.