I have 100% equity in a home valued at about 400k.

If you aren't in the state to change the locks, who's monitoring the home?

No, taking out a HELOC and spending it does not reduce your taxable capital gain when selling your home.

Home Equity: What Is It?

if there is appreciation, but you wouldn’t sell your current home tax free and buy a neighboring home to rent out, (There by raising your cost basis for additional depreciation and lower capital gains tax.) then it probably doesn’t make a good rental property. . 

I'd use an approved underlayment.Pro Tip: If it's cheap, it's not good.....at least spend in the moderate range.

Unfortunately, timing was about 2 months late and the market went dormant for larger homes in our area around late August when we had the home finished.

This home is for sale, circa 1920s. 

What are some key tips and websites that you know about that I can use in terms of RE Financing?

And partner with people you trust & have done it here in Kyle before - by far the most important tip I can give.