Zion is an odd park, because its main road is closed to you. The Zion Canyon Scenic Drive, which runs up the Virgin River valley between towering sandstone cliffs, is generally given over to shuttle buses for most of the year, and the spot where it leaves Highway 9 is Canyon Junction. The shuttle stop is a few steps from the road, with the Watchman rising behind it, a blunt buttress of red rock. The motorcycle stays on Highway 9, which means the real ride starts here, up the switchbacks toward the east.
The Zion-Mount Carmel Highway is one of the most spectacular short roads in the western United States. It follows Pine Creek out of the main canyon in a series of six tight switchbacks, climbing through pale Navajo sandstone cliffs toward the famous tunnel. Behind you, the canyon opens, and the rock walls, in shades of cream, pink and red, lean overhead. The road was built in the late 1920s and opened in 1930, a major piece of engineering in its day, and the stonework on the walls and bridges still looks tidy.
Because Zion is one of the most visited parks in the country, the junction and the road are crowded in spring, summer and autumn. Plan around it by arriving early, ideally before eight, or in the evening, when the light is lovely. Summer afternoons can be fiercely hot and thundery, and flash flood warnings are common. Winter is quieter and cold, with the odd icy morning. The speed limit is low, and rangers enforce it, with good reason: tourists, cyclists and deer all share the road.
The entry fee is payable at the park gate in Springdale, and parking at the visitor centre fills early. Springdale, just outside the south entrance, has fuel, restaurants, supermarkets and a good choice of motels, though it is busy and prices reflect the view. Hurricane, further west, is a bigger town with more choice. Carry water, a hat and sunscreen even in cool weather, and treat the walls with respect.