What I have on
Yellowstone.
If in this area of MT: We drove by
Pompey's Pillar not knowing what it was in 2009, about 25 miles east of Billings, Montana, on our way to Yellowstone. "It bears the only remaining physical evidence of the Lewis and Clark Expedition, which appears on the trail today as it did 200 years ago. On the face of the 150-foot butte, Captain William Clark carved his name on July 25, 1806, during his return to the United States through the beautiful Yellowstone Valley." Might be worth a stop, if time allows.
Likewise, if in this area of WY: Overnighting Sites & Sights in the
Douglas & Wheatland Area. Includes Guernsey & Fort Laramie Area.
Guernsey State Park -------
Fort Laramie National Historic Site ------
Oregon Trail Ruts and
Register Cliff Could use I-25 to Casper then US 20/26 to Tetons, then up to Yellowstone. Thermopolis is off this route. One could go via Cody to Yellowstone, or to Tetons, then to Yellowstone. More of a climb by going to Cody route.
We've gone by Thermopolis, WY twice to do a soak in the hot spring water at the State Bath House. Very neat. We over nighted in the Wind River Canyon in Aug '09 & at one of the Boysen State Park campgrounds by the lake some years ago. But each time, we had already gone to Yellowstone, before stopping.
thermopolis.com/todo/hot-springs-state-park/Easiest Route would be the South entry from Rock Springs (US 191/189) & I have heard from Rawlins (US 287) is not bad, but it takes one up to US 26 which is basically like going to Casper then over.
We have use the US 191 and/or US 189 a few times, but we were going up from farther west than Denver. Never used the up from Rawlins route.
From Denver, I'd use I-25 up to Casper then west from there to Moran Junction in the Tetons north of Jackson (miss having to tread your way on some what narrow city streets of Jackson). Jackson is a town in the Jackson Hole valley of Teton County.