I have a 4 hour layover in CDG. I land in terminal 2C but I depart from terminal 1. Since I have enough time I really want to meet a friend for lunch and possibly do a little shopping in terminal 2E Hall K. Is this possible? Also, I do have an american passport not a visa which some people told me can make a difference. Please help!!
Yes, you can travel between the different terminals in CDG.
Apparently, when connecting from terminal 2C to terminal 1, if both your flights are from/to outside of Schengen, you can usually connect without entering France, with the green shuttle. But in your case, you do not want to do that for now.
As @phoog commented, the shopping area of terminal 2E is in the international zone. so you should not need to cross the border into France. What you want to do is take the blue shuttle that links terminal 2C and 2E. Once you are done you will have to take the blue shuttle back to terminal 2C, then the green shuttle to go to terminal 1.
If for some other reason (typically to see your friend, since this friend might not be able to access the international zone), you want to cross the border: as an American passport holder, you can enter France (and Schengen) without a visa (it is still a border, so the border agent may deny you the entry). Once you cross the border, you can go to terminal 2E, then to terminal 1 for your connection. To go from terminal 2 to terminal 1, you have to take the CDGVal, that appears on the airport map.
Keep in mind that crossing the border may take some time. If your two flights are with different airlines, you will probably have to collect your luggage and check it in again, so that will take even more time.