I used Dragon Gym for taekwondo a few years ago. That place was legit. They are no joke. They were even on us about diet and exercise outside of class. I cannot speak for Muay Thai other than talking to those guys in the locker room but all the instructors cared a ton and were real easy to talk to. They have my vote but they are under new management since I was there so maybe do a Groupon for like 8 classes and check it out.

A cheaper place close to Harrisburg is Perry County, check around the Route 11/15 area. That is a main street with many small towns. If OP reads this, you described Perry County pretty well in your list of needs.