I realize that wifi is nearly everywhere, but I'd love to travel to some smaller towns in Maramures/transylvania next spring. Will it be difficult to find wifi? Even smaller towns? Thanks for any advice!

There are hotels and bars in Maramures that offer free wi-fi, but you'll have to buy a drink or some food. It might be better and cheaper to by an add on to your present plan. Ask your provider what they offer, then compare how much it will cost to buy a room for the night, or a few drinks and a meal. My point is that in the UK McDonalds has free wi-fi in many of its establishments but then you have to buy something, even if its just a small fries. Is it worth all the hassle of searching around?

Villages in Maramures, in general, have no wifi. The only public places in the villages are the churches, the local shop and the local bar, and they will have no internet, and for sure no wifi. Also the guesthouses will in almost all cases have no wifi and a lot of times even haven't got a computer available. There are of course some exceptions (we have wifi for example), but these are rare. You can buy a usb-stick, but in a lot of villages it will be very slow, because most are out of reach of the 3Gnetwork.
In bigger towns you will have more chance; i know for example Sighet has some more upscale bars/restaurants with wifi and a hostel where you can use the computer.