LOFAT36 wrote:
Are some routes better than others heading East into Wyoming from mid/south Montana ? Then down through Colorado & N.M. ? Any suggestions ?
I'm presuming you mean somewhere east of Yellowstone, and heading down into Wyoming from south central Montana. If that's the case, there are really limited options, depending on your preference, time frame and what you want to see/do.
You could simply take I-90 from Montana to Buffalo WY, and pick up I-25 there, and use that as your southbound route to where you want to go in Colorado/New Mexico.
Or you could take US 310 from Montana into Wyoming and go down through Worland, Thermopolis, Riverton and Lander via US 16/20/26 (sometimes combo on those roads), and then pick up US 287 in Lander and take that south to I-90 to Laramie, and then continue on US 287 south through Fort Collins CO and pick up I-25 there or in Loveland CO.
If you're talking about coming out of Yellowstone/Grand Teton area, there's a variety of routes that could work -- US 26/US 287 or US 189/191 out of Jackson down to I-90 in the Rock Springs area.
I'm sure some of the fine Wyoming folks here will chime in with preferred routes, these are just some of the options available to you. Again, depends on what you want to see/do.