I attend different types of retreats during the year. Our small group does three day retreats where we take all are own stuff and snacks. One year we brought food and last year we ate out (at inexpensive places but not fast food). We stay until 8 or 9 and then go home. We can leave our stuff there and come back the next day. Some of the ladies work so they can't come all three days but since we don't pay for it it doesn't matter. Our guild holds 2 retreats every year, one away and one where we have our classes. At the one away we bring food or eat out. At the one in town we usually bring food. Again, we bring snacks and can leave our stuff when we go home at night.
I also attend 2 retreats a year at a YMCA camp about 3 hours away. I go when the retreat is 4-6 days long to make it worthwhile carting all that stuff. I have a Honda CRV and I fill it up. We have to take bedding and towels and snacks. I always take way more than I finish, but at least I never run out things to do. They provide meals and boy are they goood.