That's a big hunk of miles for a ten day trip, 2020 miles.
Seattle to Glacier National Park is 561 miles--but they are slow miles. You will be lucky to average 50 mph. Most of the Campgrounds are closed until late May--for example in Saskatchewan where I live (and it is warmer here than in the mountains) our provincial park campgrounds do not open until May 24.
You will need your winter woolies!
Glacier to Yellowstone is 477 miles. Most experienced RV folks try not to do more than 300 miles in a day--on the flat--again these will be slow miles through the mountains.
Yellowstone to Twin Falls is 339 miles--that's a better day of driving
Twin Falls to Seattle is 645 miles.
If you guess at 300 miles per day the driving time alone is 7 days.
Four adults and 3 kids in a 29 footer may be a challenge as well. Consider a tent for the kids? It will give them some alone time.
As for things to see--the route is one long scenic drive. There are dozens of wonderful items. Your trip, according to Microsoft Streets and Trips passes by 185 campgrounds, 232 Art Galleries, and 129 Museums.
Water and electricity may quickly become issues if you try to "boondock" at rest stops. The furnace doesn't run to well if there is no power left in the "house" battery to run the fan. If you have 4 adults and 3 children all taking a shower each day the water tank will be empty very quickly. If the rental RV has a generator--then power is not an issue--but fuel for it may be a significant expense. Generators are generally quite noisy too.
There are some very inexpensive campgrounds--you may wish to look at these web sites to see what is available.http://freecampsites.net/
You will also pass by 12 Casinos--sometimes these establishments have free overnight parking for RV's--sometimes with power--and occasionally with full hook up sites (electricity, power, sewer).
Learn about dumping your black water and grey water tanks! Practise at the dealers place before going on your trip.
QUOTE(alexbetty @ May 5 2009, 06:33 PM)
We are renting our first RV. We are planning on 4 adults and 3 smallish kids in a 29' slide-out. We are leaving from Seattle, stopping at Glacier, heading to Yellowstone, and then swinging back through Twin Falls, ID and back up to Washington. At least that's the vague plan. We are doing it in 10 days.
I don't know anything about staying in RV parks, etc. And are we allowed to sleep at highway rest stops? Are RV parks preferable to campgrounds? Do we need any kind of membership?
Also looking for suggestions on routes and points of interest along the way.
Thanks in advance!