HelloI recommend to start out without using no money ...zero dollars..If you have the drive and desire to make this happen you can do it...Below is a link to a ton of free information...http://www.flip2freedom.com/

If/when somebody buys the community I'm thinking this lot may become desirable to a builder?  

Depends on your desired annual return and how active or passive you want to be.Also if you have 10,000 to start or 1,000,000 etc. 

Some markets are more desirable (say where you can rent a home for 700 and the lot rent portion is 300, and you have a good spread).  

A 15 grm is not a very desirable number Smaller is better in grm terms

Other than the 90 hour learning and exam and licensing, where should one start with little to no knowledge but desire to get into the business?

Make sure of your desired market's information every time.Best to you!

To get something in your price range that is in a more-desireable area for you and your family to live in, maybe check to see if you can get a fixer upper funded with private (or hard) money, then once it is "move-in ready" refinance with the VA loan that is available to you as a vet. 

Many if they fail right out of the gate have no desire to continue ( IE that did not work) and or lost money and can't continue no matter what they desire.

I don't think the numbers look that spectacular: First, anything that rents at near $100/ft in the Midwest needs to be in a very desirable location or a top quality property (complete rehab) and have amenities (2 BA's and a garage...you only have one bath).