A lot of great places to visit on your route.
May I suggest a Friday or Saturday night in Whitefish, MT.
Some nice little nightclubs/bars with great live music.
Inexpensive lodging in, and around town. Also, not a bad 'base town' for a Glacier Park visit.
I've listed a few other places below.
A little north of Highway 2, The North Cascades Highway.
Sort of WA State's version of Glacier Park, Mont:
Newhalem, WA and Ross lake at the West side of the North Cascades Hwy:
Winthrop, WA on the East side of the North Cascades Hwy:
A bit south of Highway 2, and Stevens Pass,
Snoqualmie Pass/Snoqualmie Falls, WA:
Dry Falls, near Grand Coulee, WA:
Grand Coulee Dam, WA:
Spokane Falls, Spokane, WA:
Silverwood Theme Park, north of Coeur d'ALene, ID:
Sandpoint, ID and Lake Pend Oreille:
Testicle Festival, Clinton, MT
Glacier Park, MT: