If I were you, I would look into the HELOC to access your additional equity.

It's sole intent is to help you get access to the property before you can even qualify. 

Finally, all the improvements we did to the house over the years were with "renting it out later" in mind.

I don't know how it will affect resale value, but since you would still have garage space in the primary home, the functionality of the home will only be improved.

If I had access to a lot more money, would I consider stopping my W2 job to flip properties and do some rentals?

Since the property was re-appraised at $480K over a year ago the area has continued to improve and seen further  increases in real estate prices.

@Mark AndrewsYou are required to first allocate the purchase price to land and the building.The amount allocated to land is non-depreciableThe amount allocated to building is depreciableYou may also make improvements to the property which can possibly be added to the basis(if not expensed). 

I'd really like to try the Brrr Strategy, and a HELOC sound like a great way to go about accessing the cash needed for a purchase and refurbishing.  

Isn't the whole appeal of "turn key" investment companies making deals like this accessible to out-of-state investors?

The four elements of CPTED are: natural surveillance and visibility; lighting; territorial reinforcement and space delineation, and natural access control.