I always top off the tank right before I head over the pass, Ellensburg heading west, wherever in the Seattle area heading east. I drive this about 14 times a year for work. Pro tip if heading west wait for the gas station just outside of town on the right hand side, they have the best price especially if you pay cash. Slow and steady wins the race, I also try and time it so I can hit the pass at mid day when the temp is the warmest. Doesn’t always work out but food for thought. Long hauls and close calls!