This a very long dayhike.
But if you are considering your first 20 mile day, this
would be a good one. There is plenty of variety to
keep it interesting, but no major climbs to make it overly
difficult. And if necessary to bail out, a hiker can
take the cutoff from Rainbow Lake down to Snag Lake.
It visits most of the biggest
lakes in the Park. And they have fine campsites for
those sensible people who will do this as an overnight trip.
The cinder fields from Mile 1
to Mile 3 are probably the hardest part; the rest is easy,
well maintained, backcountry trail.