Tteton - Lots of great advice - I'd pay attention to getting that inexpensive permit to camp on Indian land river left. If you're not rigging and camping at Sand Wash the night before you're going to have an even longer first day - 25 miles of a LOT of rowing - throw potential wind and Tamarisk clogged banks and the start might not be fun.
Melanie at RRT is fabulous - and they're worth every time for the shuttle.
The only advantage is you may be ahead of the skeeters - even Alaska can't compare with those at Sand Wash - tczues may be in for a June surprise. (I counted 72 bites in one ankle in 2011 and I reeked from bug spray.)
Restrac2000 was spot-on about wind - it can blow you backward in the middle of a rapid - I was wishing I had a helmet with face shield because of spray blowing off the river - we couldn't even set up tents until after dark waiting for a lull in the gale.
Be really cautious about bears - we had lots of tracks all through our camp at Range Creek - we packed up the kitchen and trash after dinner and made sure we had clean clothes in our tents - still had tracks on the boats in the morning. This is an interesting read: Utah Local News - Salt Lake City News, Sports, Archive - The Salt Lake Tribune
I like Nefertiti for my last night on river - it has a restroom!
All that said, you'll love the side canyons, creeks, and petroglyphs. I hope you come off river saying there wasn't any wind, skeeters or bears!