Thanks, "littlemo".
We will be leaving Cedar Park (Austin) Saturday morning going up Hwy-183 through Brownwood, Abilene, Lubbock, Amarillo, Raton pass, front range, etc.) and pulling into GTNP Monday afternoon/evening, giving ourselves 3-days travel time.
We will be in Jackson Hole area five nights (Mon-Fri) with about four full days. We will canoe/hike/fish/bike most of that time. Plus whitewater raft the Snake River (of course) and a day in Jackson (Alpine slide, etc. for kids).
We'll pull out Saturday and head up to YNP through South entrance and work our way up to Madison (maybe a picnic and canoe stop on Lewis or Shoshone lakes). We'll spend 2-3 nights at Madison flyfishing, hiking, touring, visiting town of West Yellowstone, etc. and then work over to Fishing Bridge where we'll spend the remaining 3-4 days of our trip. We will plan to exit East entrance and follow your suggestions for some of the sights/attractions for our homeward bound journey.
NOTE: You are so right about the expanse of Yellowstone. We've already settled the matter in our hearts that we cannot hope to take in all the majesty this vast park has to offer us on this first (of hopefully many!) visit. We look very much forward to future adventures and discoveries and will continue to look to experienced friends like you and the others for tips and advice! Sincere thanks!