There was a very good thread here about Esther maybe a year and a half ago, pre-crash.
http://www.adirondackjourney.com has an excellent photo-guide to this and most other summits.
My dog & I did just Esther in September '03. We somewhat deliberately took pretty much the whole day to do it, although considering that I hike at the pace of an arthritic snail and we took several extended breaks, half that time is more than most folks here would require.
We found lots more good views on this route and at Esther's summit than it gets credit for having. Do bring plenty of water, though. The route's bone-dry of anything potable, at least during dry spells.
From the trailhead at Wilmington Reservoir (off Whiteface Memorial Highway), the trail up Marble is typical -- very rocky with occasional little mud-wallows even in dry weather -- nothing at all steep, but relentlessly uphill without relief. The trail junction near the summit of Marble was marked with a very small cairn right on the trail. Continuing straight ahead, after a steeper stretch the grade eases a bit toward Lookout. The toboggan shed on the south side of the DEC trail means you're close to the start of the herdpath for Esther. Can't miss it, it's five minutes past the shed and marked with a very large cairn. Several cairns atop Lookout indicate paths to campsites, just bear left and head downward. The infamous bog is now well and easily skirted to the right by the herdpath. The grade is pretty easy and although the path is quite narrow toward the top it's a snap to follow. Little-loved Esther turns out to afford a largely open little summit with surprisingly nice views east and southeast and Whiteface huge to the south.
Can't comment on Whiteface, I'm saving that for #46 (sometime in the 22nd century, at this rate).
Happy trails --
Uncle Butch