If you are leaving Seattle in mid-June you'll have the prime time to travel up the Alcan and the Dalton. I wouldn't plan for snow days, you'll be fine. Think about Dawson for D2D on solstice. If you haven't been here before you're in for a great ride.
2007 R1200GS; 2006 DL650 V-Strom; 2011 F800R; 2013 CRF250L; 1995 R1100GS (sold); 2006 Ducati Multistrada 620 dark (sold); 2013 F800GS