No commercial lenders will talk to you at the $20K level (about $50-60K would be the bottom end), but private money and some hard money lenders might be an option.Flipping of houses is considered a business and is therefore not entirely tax-sheltered in the IRA. 

I am looking at the strategy of taking out the HELOC and then putting everything into it using it as a checking / savings account, and using it to help pay down the principal faster.

To make a decision on the route to take, you have to do some homework first which entails, learning how much $$ you have/need for each, how much financing if any will you be qualified for, what's your level of expertise in either, will you have partners going in, do you have the team of qualified professionals for each.

I don't have anyone in my family or friends that's owned real estate so it's hard to find someone to lead me in the right direction.Property is a fourplex in a mid level neighborhood.

Look at your own risk tolerance and stay within your own comfort level. 

One benefit I have seen to a HELOC is that you can set your direct deposit up to deposit into the HELOC and use it as your checking account perse, and naturally, you can pay off more, and faster.

I think whether turnkeys are good for out-of-state investors completely depends on:the investor's goals and interest levels in what kind of investing they want to dowhat turnkey company they work with and what they buywhether or not the investor is prepared to do their own due diligence and maintain an eyeball on what is going on with the property, even when other people are primarily managing itI've almost always bought turnkeys out-of-state and I've loved them.

I could imagine a commercial level LVP could handle a few keg parties.  

Vacancy is low.Repairs are low (2 furnaces, 2 ACs, etc = high capex).Nothing in here about leasing fees which can be substantial especially on a multi-family.You're banking on the property appreciating faster than expense/rent inflation - why?

It is definitely possible, but the question here would be how long would it take to reach the level of appreciation that you are looking to achieve.