I get that you are saying your yearly opportunity cost for pulling the 300k out of the stash to buy a house is 12k (aka 4%), so $ 1000/month, which is somewhat right, if you neglect taxes and potential of higher appreciation for simplicity purposes
But don't forget that your 1000 k then have to cover MORE than your mortgage
You will still have to pay taxes, insurance, maintenance and all that good stuff, you'll have to take into consideration.
If you can rent out your current house for a much higher ROI than your invested money that's great, especially as you won't have to pay the transaction cost for selling it (I cringe only thinking about paying realtors 6% plus all other fees etc)
Is there a way to rent for a while in your desired area and see how things are going? Especially if it's far away from where you live now, you don't want to rush into a buying decision purchase, without being sure that this is a good solution for you.