Bryce Canyon is relatively a small national park. Unless you really want to
see every inch of the land, you can probably complete your tour within one
day or even less if you want to save your time for other places.
If you have very limited time (like 2 to 4 hours), go to Sunset Point and
Inspiration Point to experience the visual impact. They have perhaps
everything about this park. If you are confident in
your physical condition, take the horse trail down Sunset Point to have close
contact with Hoodoos. With a little more time you can visit other view points
north of rainbow gate such as Sunrise, Paria View and Bryce Point.
With minimum extra 2 hours you can extend your vision to south of rainbow gate
for Rainbow Point, Ponderosa Canyon and Agua Canyon. We didn't take the under
Rim trail so we really don't know what we missed. However, just judging from
the scene nearby the parking lot, I would say that they are not as impressive
as Sunset and Inspiration, although they do look different.
If you really want to experience the most of the park or if you are
a photographer, you need to
stay overnight for sunset and sunrise. It's the luxury we didn't have.
People usually don't just visit Bryce Canyon alone. It is very close to Zion
and Capitol Reef. The distance to Grand Canyon and Arches/Canyonlands is also
within reach (depends on your travel style, of course). For aggressive
travelers these parks can be packed in one trip.