Don't forget at that price it isn't a multiple entry, so if you leave the country remember to get a reentry permit. Congratulations on getting the extension relatively hassle free.
I don't know how close you are to Kalasin, but I have only been treated well there. Also in the three times I have been there, it has only been me or one other.
Remember later you may want to apply for permanent residency or even citizenship. I believe they are based on how long you are attached to your original visa via extensions. To change to an Ed visa you might be breaking that chain, better to keep it simple. Good luck with your studies.
Go to Savannakhet, you can get a one year multiple entry Non O based on marriage, no financials required. You do have to leave the country every 90 days, go to a bordering country stamp in, stamp out and back to Thailand.
The easiest would probably go to Suvanakhet and apply for a non O multiple entry visa based on Marriage, no financials are required. However you do have to leave the country every 90 days, but you can do an out and in.
The closest spot for you to stamp in and out is Malaysia. If you want to fly there are or at least used to be flights from Phuket to Penang, do you might want to take advantage of the convenience.