I have a similar setup with an NRS frame on a Jack's 16 ft cat. My front opening has a netting cargo bay that barely clears the water. If my kitchen box is being used (an action packer-like plastic tub), it drops in there (nice as it makes it very easy to load/unload off the front of the beached boat). If the group is using someone else's kitchen, that bay holds misc stuff that can get wet, like a water jug, chairs, cases of beer, etc. I made a 2 x 6 ft wooden table that serves as the bay lid, kitchen table, and a backboard. A paco pad goes over that, with 3 girth straps cinching it down to the lateral frame rails and serving as passenger grips. 2 passengers can sit on the paco pad. I also have a paco pad over the top of the river bags that I stuff in the rear bay - sometimes a passenger will lounge on that to balance weight or stay more dry.