Immigrant Hill is the popular name for what is correctly called Cabbage Hill and is often mislabeled as Deadman's Pass which is a rest area on I-84. Going east to west, it's the descent of Cabbage Hill that's the issue - 6 miles of 6% downgrade. The road has multiple lanes and there are separate speed limits posted for trucks based on weight (from 37 MPH down to 18 MPH). We just pulled in with the slowest group of trucks and went down the hill in second gear with the exhaust brake doing its job. Having traveled that route and looking again at the map, I don't know of a better route.
Rob
Edited to correct typo.
U.S. Army retired
2020 Solitude 310GK-R
MORryde IS, disc brakes, solar, DP windows
(Previously in a Reflection 337RLS)
2012 F350 CC DRW Lariat 6.7
Full-time since 8/2015