To all that gave such great advice...THANK YOU.
Our last week of March San Juan trip was perfect (sunny, chilly, but very little wind), water in the 410-600 cfs range, and the gear barge worked great. Some notes:
Our 15' NRS Otter was loaded - I wanted to try running it totally self-sufficient, so the only group gear our friends boat carried was the firewood. We had:
-charcoal (20 lbs)
-20 pound propane tank
-10 pound propane tank (don't ask)
-130 qt cooler
-20 qt day cooler
-full kitchen box (with two DOs)
-first aid kit (fat 50 ammo can)
-tool and repair kit (fat 50 ammo can)
-dish washing buckets (4)
-water filter kit (3 buckets and filter)
-tent, sleeping bags, etc for four
-5-gallons of water
-food for a week
-lots of beer
Sealing the plywood with epoxy was EXCELLENT advice! With such short notice I had to use an indoor "bar top" type epoxy that I thinned using lacquer thinner. Took a couple days to cure, but the wood is bomber and looks brand new after a week of use.
I drilled a hole in the spare cap of my Scepter 2.5 gallon water jug and put a crockery type lever action dispenser in for the kids to be able to use. Worked very well.
Extra-wide table covering the front two bays was a great lounge for the fam, and was not too heavy for me to muscle, even made from 3/4 inch plywood. I think I'll upgrade the plywood frame to 2" angle aluminum for more rigidity. I'll put up a post of the table in time...
Deck paint with rubber aggregate (see a previous post in this string) held up OK. I didn't have a chance to put the recommended three coats on, but two kept the water out and it is VERY non-skid and skin friendly. Next time I'll epoxy coat the decks and then put the deck paint on.
Mini-bay for two rocket boxes behind the rowers seat was a great idea. Kept the groover in proper position, but unfortunately it had to be loaded early in the loading phase.
The kitchen box was heavy (3/4" plywood sides, 1/2" top and bottom, 10" and 12" DO, a 10" cast iron fry pan, etc). However, with two people, it was easy enough to move and we still wanted to have it in camp every day.
The water filter setup worked well. Had two 5-gallon buckets for alum settling, and a 2.5 gallon bucket with a bung fitting in the bottom that is connected to a 10" filter with a carbon filter cartridge. Once the sediment settled, I added the perscribed amount of bleach. After an hour or two, I poured the water into the 2.5 gallon bucket sitting on the table (positioned over a hole in the table). The hose to the filter ran through the hole in the table, and the filter output ran into the water jugs. This setup can be seen in the first photo. The 0.5 micron filter I bought wouldn't flow water by gravity. I had to change to a 5 or 10 micron filter for gravity to work.
Time to upgrade the cookstove. Our Coleman two burner failed the second night (the copper supply line inside spun and broke - not field fixable). I brought a backup stove I'd never used before - a $10 used Coleman single burner (pictured below). Of course we didn't have a small bottle, nor did I pre-rig a stand for the stove before we left. In the first photo you can see the stove perched on 5 beer cans filled with water for stability. The "PBR stove" worked great! Cooked for 8 people for the next six nights (including a couple off the river). Yippee for backups.
Once again, thanks to all that posted advice on my rig in this post, and for all the other posts where people share their ideas and experiences. Man, its nice to have this forum!