Matt! --100% yes! You and your wife will LOVE Texas! Congrats on your equity! So you've got a couple courses of action. Also, have you spoken with a financial advisor or a CPA to help max our your decisions? Definitely talk with a CPA in Boston, or let me know if you need a Texas one. If you need a new financial advisor or CFP, I got a Texas one too for ya.
I do know that If you decide to sell your home in Boston before the move, you'll avoid paying capital gains tax IF you reinvest your sales proceeds into your new home within 2 years. If you and wife decide to downsize to a smaller, easily affordable home down here, you'll definitely be freeing up more money, plus Texas as no state income tax!
Just things to keep in mind if you're planning to get rid of your Boston home --prepare to pay real estate commissions and other closing costs on both sale&purchase of the home. Pending your current market, you may even need to sell your home less than you would like in order to move quickly.
With the HELOC option, you can keep your home in Boston as a continued investment rental/access equity without selling, then build quickly with your HELOC funds to purchase your Texas investment properties immediately. Hope this helps.
Should you pull the trigger on whatever you choose, welcome to Texas! Your quality of life should skyrocket.