Off the top of my head (or, as the EPA says, your mileage my vary):
Dam to the Gates is ~45 miles. All the nice camping is in the B section below Little Hole - you'll be competing with fishermen for those sites. There are a couple camp sites in the wildlife sanctuary (one at swinging bridge, one maybe four miles above the ranger station), but they're not very nice. The water is really slow once you get below Swallow Canyon - which is a really cool 2 mile point of interest in the midst of floating a bunch of boring. I've seen moose along that stretch pretty regularly though, which is sort of fun. The park wants you to get a play permit now to float that stretch, which strikes me as completely absurd - cause there ain't no play! A liquor license would make more sense...
Below Split you better like bugs, flat water and potentially wind. I launched from the Ouray wildlife refuge at night one time (long story), threw my 'yak on my raft, and forgot my spray skirt for that rare play wave in Deso. Fortunately I was able to paddle back upstream the 4 miles to the car from where we camped without too much difficulty to retrieve it. Telling... It's about 100 miles from Split to Sand Wash. There's quite a few beaches at lower flows, and some pretty bluffs similar to Sumner's Ampitheater sort of here and there. The camping at high flows is primarily beating back through the tammies or private land. The cottonwood shaded beaches that you can find in Deso aren't there so much upstream. I don't know what the rules are with the Ouray refuge, and the Utes will want you to buy a camping permit from them to stop on their land. If you plan a resupply at the bridge in Ouray, be sure not to park your car there - the tanker trucks that pump river water for the gas fields don't always back up very carefully.
Let me know if you have any specific questions.