You would better serve yourself and find an investor friendly Realtor in the area your looking.

I never served in the military,  but I think I'd want to choose a duty station based on advancement opportunities and then build a real estate portfolio on the side.

It also seems like there is a minimum size for pms to have enough staff to handle everything properly.

My units are larger 3 and 4 bdrm townhomes, 1600-1800 sf each, intended to serve families.With a mid-range construction budget, what items are worth splurging on to get improved rents? 

A loan may make sense, but do you want the extra paperwork for that size of a check?

You have to occupy within 60 days and most landlords aren't going to serve the notice to quit for you because the reason they want to sell is because they don't want to deal with the tenants.

The criteria I am trying to pindown to help inform my selection process is:Avg MFH Cost, Avg Rental Size, Avg Rent, Avg Vacancy Rate, & County Property TaxesI believe I've been able to determine fairly accurate numbers for Vacancy Rate, & County Property Taxes by Googling, but the others are a bit more elusive.

Since you're doing out of state, the size of the location determines if you can justify the Admin cost. 

Most of them serve clients in all 50 states.

Everyone has a different goals and investment criteria, so this is not a one size fit allkind of situation.I will suggest that you clearly define what you what and do some research then go from there.A local Investor-Agent can help shorten your learning curve and save you a lot of headaches asthey tend to understand the market better.Use Niche.com, Greatschools.org and Msc.Fema.gov for your research.Goodluck and go make it happen