We found it varied different days, primarily depending on how long we expected to be in the parks. We use DS's wheelchair to carry the load. On a long day, we would have our soft cooler, a large tote bag with non-perishable foods and for jackets and ponchos, my purse, a camera bag, and DD19's purse. If we weren't staying long enough to carry in our own lunch, the big tote bag would at least be emptier, but might still be along with jackets. Sometimes it was replaced by a plastic grocery bag with the ponchos. Sometimes I took a backpack instead of the tote.
I also have a pin trading fanny pack, but find it easier just to keep them in my purse in a bag and maybe put a couple in my pants pocket. We only trade with CMs.
Sheila