Seattle to Boise route help
It depends on your perspective of scenic. It's one day drive via I90/I82/I84.. Even-though part of route not senic it's well worth taking as you will be going through some of key passes and mountains (Yakima).
- Snoqualmie Pass
- Mountains drive and scenic overview I82 (looking towards Ellensburg), nice picnic stop on top of hill
- McKey Creek National Wildlife refuge off I84 (if you have some time)
Alternatively you can take US Route 12 just south of Tacoma through Mt. Rainier Park, however at this time of year I highly recommend starting out very early from Seattle to beat traffic and get to park as early as possible around sun-rise. This route will be US12/I82/I84.