191 from Rock Springs Wy to West Yellowstone Mt.

191 is an easy, pretty much level drive except for a couple miles of maybe 6-7% downgrade just before Hoback Junction. From there turn left and go to Alpine Junction, then route 26 to Idaho Falls, then route 20 to West Yellowstone. Don't be tempted to take the shorter route up to Jackson followed by route 22 over the Teton Pass. 10% grades and many sharp curves on 22.

You could go through Grand Teton and Yellowstone Parks to get to West Yellowstone, but there are several 6% grades plus three crossings of the Continental Divide on that route, plus lots of traffic in Yellowstone. Going around through Idaho is longer, but easier by far.

Would that be turning left on hwy 189?

turn left onto 26 south or 89 south.
there's a federal campground on 26 west of alpine just below the dam, a few miles from alpine.

OK, from looking at Streets & Trips, it looks like 191 ends at Daniel Junction where it meets 189. You need to continue northwest (to the right) past Bondurant to get to Hoback Junction. At Hoback Junction 189 goes to the right up to Jackson, while 26 goes to the left (south) to Alpine Junction, which is near the Pallisades Reservoir. A right turn at this junction will take you alongside the reservoir and on to Idaho Falls.

Go with Cloud Driver's route! Hve taken it many times with a 36' DP and a toad.

Thanks for the replies, it definetly helps me plan my route.

What about fuel stops along this route? are there any easy in/easy out truckstops or fuel stations? I am limited in my being able to turn in sharp confined spaces. I am right at 61' in length.

I've driven all possible routes that I can find on my way to YNP/Tetons over the years if for no other reason than a change of scenery. North from I-80 as well as South from I-90. None are difficult drives, but like most areas in the western states, stop for gas around a half tank. The route north from I-80 via US 89 & US 189 is a beautiful drive along the Snake River on your way to Jackson, WY.

Easy fuel stop in Boulder at the boulder store with good food also. Highline Trail rv park 1/2 mi. south has big pull through FHU and terrific views.

Cloud Driver is right, going through Idaho is longer but would be, in your case, better than trying to thread through downtown Jackson! (There is a truck route through Jackson in case you do - watch carefully for it. Easier to find southbound than northbound. Definitely preferable when towing the rig over going the regular route thru town.) 26 from Alpine through Swan Valley, Idaho is one of the prettiest drives we've taken (and can be spectacular in the fall); good road, and there's a nice rest area west of Swan Valley - good place to stretch your legs.

Your main climb will be on US 20 on Ashton Hill, just north of Ashton as you head up into Island Park. It's only a few miles. There has been construction on that route this summer; we haven't been there for over a month, so not sure what the road conditions are there now. Dial 511 from home phone or (if you're in that state) from your cellphone and you can get local road conditions with minimal number-crunching - works in the states around here, anyway.

Gas stops: if you do take Cloud Driver's route, fill up in Alpine. There is a gas station there your rig will fit into. Nothing for big rigs after that until you're basically in Idaho Falls. Island Park has a few stations large enough for you - keep an eye out while driving through there. West Yellowstone's gas is A) very expensive and B) very few large gas stations capable of holding your rig (especially with the trailer in tow).