I haven't been through lately, but I took a geology group from SUU of about 18 through Round Valley Draw once. Most of them were inexperienced/out of shape and did just fine. I brought webbing to sequence them in and nobody even used it. I remember Bull Valley Gorge as being comparable with only one spot to mention at the head of the canyon (10 feet). My recolection of the canyons is that they weren't prone to hold water. You should be just fine.