Elevation from Seattle to Leavenworth (Washington) via
Max elevation: 4093 ft / 1248 m Min elevation: -191 ft / -58 m Elevation change: 4284 ft / 1306 m
Max grade: 32.8% Min grade: -32.3% Steepness score: 21 + 3278 + 18796 + 4 = 22100
Distance: 117.32 mi / 188.81 km Travel Time: 2 hours 15 mins
It looks like one possible route that might be flatter would be to go through North Bend (Oregon), but make sure you double check everything if you're planning a road trip.
Elevation data comes from different sources and may not reflect true
driving conditions, so talk to other RVers if you're concerned about