Do yourself a favor and rent rafts at Curry! On another trip, with the same family, rather than major hikes, we rafted two days. This was very enjoyable and all had a good time. The first day, we all had our own rafts. I had purchased a sizable raft, actually coast guard certified to carry 4 people, and I bought smaller ones for each of the kids.
The second day, after deflating the rafts for the bus ride back, I exploded our oldest daughter's raft, so she got the big one, and we rented one for us, and the younger kids. One of the smaller rafts was delegated to carry our ice chest.
If you have your own raft, all you have to do is rent one of their life vests and it includes the bus ride back. You do have to deflate your raft to put in the storage compartment.
And be sure and bring your bikes or rent them. The bike paths are very nice, although some morons do use them as hiking trails, so be mindful of that.
Another thing you might do, and I am not sure how old your kids are, is attend a marshmallow campfire talk at Happy Isles. We did this and they had plenty of marshmallows and we all had a good time. The ranger had a guitar and sang songs.