A/C runs very cold and then will cycle off for a period of time and then cycle back on. The camper stays comfortable and am wondering if this is normal for a 110 volt A/C unit ??? Still would like to know what type of freon that the original 1990 A/C unit took or still takes.

I'm betting on "12"

Sorry you loose, most all A/C's prior to 2000 would be R22, but better check the model tag. The cycling off and on is normal, if the room temp is comfortable, you are in good shape.

You are correct when we are talking about residential and commercial A/C units.

However in my limited experience the RV units that I have seen were more closely related to a "window unit". And on those, the early ones were R12 and they later changed to R134, just like a refrigerator.