I was in close to the same boat, and choose to stay pat and keep the house.
I see your numbers different . Bought house for $340K, could sell for $630K. That would leave you with a capitol gain of $630-340 = 290K. If you have done any improvements/repairs to the house since purchase, they also come off the capitol gains side. I.E. 10K for a new deck, new HVAC, HWH, windows...
Cap Gains will likely be much less B/c 6% commission on the way out. So the $630 becomes $592.2K, so Capitol gains would only be on $252.2K @ 25% your tax bill would be $63K. That is if you hold it for another 36 months. Holding for another 36 months will get you Call it $600 in cashflow + another $1,000 a month = $1,600 * 36 = $57,000 in loan paydown and cashflow. That is close enough to call it a break even.
If you take the money now you will need to figure out what to buy and your interest rate will suck. Whatever appreciation happens will likely be the same between old and new investment.
I would think about taking a 100K HELOC against the house. That will make you less cash poor. Rent the house and if you find something in the new state you will have 100K for down payment or purchase outright. The HELOC $$$ can stay so you are not paying interest unless you need it. The one I got, they forced me to take 5K of it out and keep it for 12 months, so they could waive the closing costs...
Then in 2 years you will have $38,000 in cashflow and paydown. Sell the house then, or revisit the Capitol Gains question.
We are hoping to sell ours with owner financing, wrapping the underlying mortgage in 2 years. That way we will get the benefit of not paying capitol gains tax and picking up the spread from the low interest mortgage and a higher market mortgage rate as well as market rate for our equity position