Originally Posted by Grady Camping
... the route back to the 90 through Missoula. Based on what we could find, we are estimating that route to be about 7.5 hours, not including stops to stretch. Would you agree?
Well... That really depends on how Fast you drive...
Unfortunately, the 7.5hrs average from most Mapping Apps fail to take into account several facts of both Rural Roads and Trailer Towing:
1) Several of the Roads early in the Route are nominally posted as 55mph but are realistically driven at 40-45mph due to Corners and Grades.
2) Portions of US-93 around Flathead Lake are Stop-n-Go Driving through the equivalent of a couple of "stretched-out Resort Towns" on 2-Lane Arterial (while the bulk of US-93 is Limited-Access 4-Lane Separated Highway or at least has long Passing Lanes).
3) The long stretch of I-90 is posted as 80MPH in Montana and 70-75MPH through Idaho - yet most "Good" Trailer Drivers will be holding their speeds closer to their 65MPH Tire Rating. And since that limits one to the Right-hand Lane quite often, one also gets slowed by Big Rigs on both sides of Mountain Passes.
I'd say you'd need to add an Hour to that estimate - 8.5hrs Drive Time.