Depends on what sort of "recreation" you do and how low gears are on your bike -- and how much "tacking" (weaving from side-to-side) you do when climbing up the road.
Originally Posted by datlas
Also how early in the morning you're able to start climbing so you can get up and down before they open it to car traffic.
If you ride in the evening after they close the road to cars for the day, would likely involve descending in the dark (or moonlight?) -- myself I'd rather do my descent with best light for seeing animals coming from the side.Measuring the Difficulty: I've read that the steepness is a fairly steady 8-9% grade. (I've climbed it on cross-country skis, never on a bike, and 8-9% fit my experience that day). Around 3500 vertical feet of total climbing if you start down by Wilmington, less if you start at the gate of the toll section. So from a pedaling perspective it's basically just a long slog.
There might be some times in late autumn when the toll road is no longer open for car traffic for the winter but there's no snow covering the road yet - (but right now today I've heard there's already snow on it)
Scenery: On the other hand it does have some big views of the northern Adirondack mountains from much of the road -- unusual for cycling climbs in the eastern US. Likely most spectacular in springtime when there might still be some snow on the surrounding mountains (and alongside the Whiteface road) -- just after the Whiteface road gets free from snow. Something to think about is allowing extra time to hike from the top of the road to the summit of the mountain for even bigger views.
The simplest answer to "Is this reasonable?" is to find some 10-12% grade hills to practice on closer to home. When you feel comfortable doing repeats on those hills (perhaps with some alterations in gears and riding techniques), you're probably strong enough for Whiteface (on a dry non-windy day). Which still leaves the question of how early in the morning you need to start riding in order to be fast enough.
P.S. A more interesting long climb (more variations in steepness) is the north side of Mt Greylock starting near Adams MA (but with much less views from the road while riding) which last I checked is open for cyclists all day long (when snow-free).
And there's several tougher climbs open on public roads in southern New York and west + north New Jersey (also in New England states) -- so if you live near those areas, there's no need to drive so far (or work around daytime restrictions) to get to a serious challenge.