Hi Matt -
Well, I had a long post I was going to finish up today - -
And I accidentally deleted it. Meh.
First, I'm no fan of the Great American Rail Trail.
I see it largely as a promotion piece for Rails-to-trails.
Through nearly all of Wyoming and most of Montana it is imaginary.
Nor does it make much sense since there are excellent paved roads -
and even better forest roads galore.
And it is - what word should I use - arrogant? -
to draw a line through Yellowstone National Park
with the false implication that it is somehow a planned route.
The stretch just north of Gardiner is an example.
A study is being done to revive a rail route abandoned 70 years ago.
Nearly all of the right-of-way has reverted back to private owners.
Not only is it virtually impossible, it would also be prohibitively expensive.
Meanwhile, there is the practically empty and gorgeous East River Road.
<<<>>>
If you've already done the TransAm, why not head thru Butte?
Butte has an amazing history - one of the greatest cities of the West.
It's seen some hard times since it was the biggest city between Chicago and Seattle.
But ya gotta love it.
Hwy 1 from Drummond thru Phillipsburg to Anaconda is a great ride.
The Rock Creek route suggested above has I-90 riding and quite a few miles of uphill gravel.
I suggest heading due east out of Missoula to Ovando then on an empty small road south to Drummond.
https://ridewithgps.com/routes/43882814If you want to cut off the big Ovando loop,
you can cut over the Garnet Mountains thru the ghost town of Garnet. Tough but doable.
Saves 30 miles.
http://www.garnetghosttown.org/From Butte, you may wish to take old roads to Three Forks -
Then some busier possibilities thru Bozeman to Livingston.
THEN - - you can take the East River Road south to Yellowstone.
Best - Jama
https://ridewithgps.com/routes/43883004