To the OP, moral/ethical/legal issues aside, you are seven years into a 30 year fixed mortgage, you have 23 years left, and you are on this board because, in theory, you are interested in retiring at an age that you can enjoy yourself for a while. Since your income hasn't gone down and your payment hasn't gone up, I'd expect you can find a way to make it work - just don't do any more remodeling, that's freaking expensive. If you look at the amortization tables you'll see your payments are starting to be significantly larger principle payments and smaller interest payments. You've already paid half or more of the interest at this point, pay off the house. See this through. Your alternative is a messed up credit score, no home but one you rent, and a huge setback on your ER goal. Don't underestimate how much a crappy credit score will cost you in stress and actual $$. You have to separate the emotional toll of the loss in equity/value from the debt itself. Forget the perceived value of the house, you owe ~$300k. If you've got income for renovating, use it instead to pay this down. If you put an extra $400/month on the mortgage starting now you'd have it paid off 17 years from now, and would owe less than $200k 7 years from now, by my quick math.
BTW, this site is great for playing with numbers, excel spreadsheets are my favorite for planning long term :
Spreadsheets
Alternately, you can stop paying and not say a word to the bank. It's taking them at least a year to foreclose now. You can then put that "mortgage payment" into a savings account and go from there. If a car is truly on it's last legs, you'll need to pay cash for it's replacement anyway.