However, after you get some experience, you probably want to get a Private Lender since this will allow you to keep the majority of the profits.

You don't need to know everything to get started; you need a foundation to build on, and the rest will come through experience and then refining your education.You can build a basic understanding of investing in 3-6 months.

Would it be a good idea to get a real estate license and work in real estate or are there other options to get in Missouri to get real estate experience without a license? 

I'd love to hear anyone's experience in the construction of a duplex on land.

That was a learning experience.  

@Keith AngellFrom my experience, both a HELOC and refinancing have their advantages depending on your goals.

A minority of 401k providers will let you transfer the loan to a new provider, but I have yet to experience that option with any 401k I have had. 

You lose all of the control and these are long term investments - but in my experience the returns match what I had on the active real estate and I am hiring professionals to manage the assets.  

Risk mitigation is crucial, and learning from past experiences is beneficial.

Great that you have experience rehabbing.