Well, I don't know about rural, but it sure has an American feel to it. It seems to have made inroads into BE, because OED marks this usage as "Orig. U.S.".sounds like rural American
I don't think the logic of that is entirely impeccable.but when I was a child I watched lots of cowboy films and they spoke like that.
Way too is much more common in spoken American English, but I guess it still feels sufficiently informal that it tends to be avoided in writing. It has nothing to do with urban vs. rural usage.I'm glad to see (from ngrams) that "far too" is still very much more popular in AE than "way too", and "much too" is inbetween. In BE the contrast is starker, with "way too" being relatively less popular than in AE.