But if I leave the military in 5-10 years, the amount in the 401k won't be high enough to matter, plus I cannot access it (apart from the self-loan feature which may or may not be available when you are no longer active), until age 60 or so.

As far as what to look for in your purchase -- location, age, sq footage, lot size, future city infrastructure development or redevelopment, potential rental rates (near hospital to rent to medical staff), are you looking for cash flow are you looking for appreciation....etc ... etc... 

It's great that you have a passion at your age.

I think if I could get started now at such a young age then it is possible for me to really go somewhere, and that is a huge motivation for me. 

However, even at your net worth now, you will likely have to continue working well past the age I would like to retire in order to ensure you can draw off those investments long enough.  

What is the age of the property?

If the person sitting next to you is late 30's, looking at another 25 years of daily grind, and sees you are 5 years from retirement at the same age, they will get jealous.I am with others who keep real estate business hours communications to texts and emails, and take calls at lunch / before /after work.  

In this day and age it's a wonder he didn't end up at Guantanamo Bay I guess.....:-)In my opinion, a business card would be a likely choice.

Age of house requirement?

Now, when I sell, then the market CAP is of interest.I would need to know more about the local economy, the building's clientele, the business' performance (is it operating efficiently, if there is room for improvement, how much), the age of he building and its degree of obsolescence and deferred maintenance.