Best possible advice: buy a couple of books and plan your attack. IIRC, we thought Yellowstone Treasures was the best. Lots of good info and totally unexpected tips, like blackberry margaritas and nachos at Signal Mountain Lodge near Jackson.
Firedoc, if you go in May (maybe not possible since your hosting gig starts in May) there may still be some snow to contend with. The road north from Canyon to Tower opens last, and in some years not until mid-may. That said, May is incredible for babies - first the bison and then elk. Bison calves run in and out of slow traffic like big, happy dogs. You can dodge the crowds and families if you go in early September and the weather is still usually nice - much warmer than early/mid May.
When we go wolf watching in the Lamar Valley in winter (going next week), we take our SUV, but otherwise we take our Miata. We haven't visited with our MH yet, but our turbo Miata is our toad. That should tell you about our mind-set - we like to drive and enjoy a good mountain road. Our typical trip has us moving around. We'll stay in West Yellowstone and do Old Faithful and the surrounding areas, then get up and do the central section of the park (basically Canyon, the lake and exit to Cody in early afternoon. The next day we will drive Chief Joseph Hwy (Dead Indian Pass is a series of 35 mph sweeping hairpins), then the "pile of intestines" Beartooth Hwy up to Red Lodge, have lunch and drive it again. Charles Kuralt (sp?) called it the most scenic road in America, but it opens late in the spring, so plan accordingly. We'll stay overnight in Cooke City, get up before dawn and go critter watching in the Lamar Valley, then on to Mammoth Hotsprings and the Norris Geyser Basin. Wolf, grizzly, black bear, elk, bison, moose, bighorn sheep, mountain goat, coyote - we've seen them all in a 24 hour May "flyby" visit on our way home from Moab.
If you want to see wolves and run across a yellow Nissan SUV with 3 antennas, follow that truck. If there are wolves to be seen, Rick will find them.
If you like to get out and explore, leave the rv in TF and drive the toad. There will be dozens of opportunities to pull over and see something awesome that you won't be able to take advantage of in an RV. Take a spotting scope if you have one. If you don't, be polite and someone with a scope will likely ask you if you would like to take a look through theirs.
Drive every single "alternate route" in the park. There is something cool to see along each one.
If you aren't going to move around (like we have done on our Miata road trips), the only place to setup base is in West Yellowstone. Everything else is too remote.
There is an RV park in the small town of Gardiner (north of Mammoth Hot Springs), a really nice one about 30 miles further north on the banks of the Yellowstone. Nothing to add about campgrounds on the way from Cody, but I wonder if there aren't boondocking opportunities along that route??
I'm not sure what the road construction calendar looks like for 2013. The last few years have had a lot of activity, with a road only open for bursts during the day and closing over-night.
Dang, I'm glad we're leaving Thursday for Yellowstone. Writing this without a visit planned for the near future would have been difficult!