We had something similar happen, except a friend (former friend) asked us to join them. Oh no, wouldn't do it. We didn't have our own camper so we rented a class c for the trip. When we got there she sprung it on us that she invited several other families too, all of which came without ANY SUPPLIES! So not only did we have no idea who these people were, but she dumped it in my lap to FEED THEM and chauffer them! To make it worse, her people were horribly rude. By day two I told her I'm done. We went out to eat and spent the rest of the time by ourselves.
I have since learned to say NO! We also purchased our own travel trailer and have always found someone to chat with at almost any given moment. You'd be surprised how much you will find you don't need anybody with you to enjoy camping. Less is best!