Hmm. West Mountain can be VERY windy that time of year, and I don't have your fancy-schmantzy WM sleeping bag.
But sure, that sounds like a plan.
There are a ton of nice shortish loops that can be done from there, with a lot of cool archaeology. The Cornell and Edison mines, the Dunderberg Spiral Railway, Doodletown, the 1777 trails are all in reach. If I'm planning the thing, I think I'd suggest spotting at least one car down on 9W so that those who want short miles can exit from there without having to climb back up Dunderberg/Timp.
If memory serves, there's also a less exposed campsite (marked with an F for 'fireplace' on the trail maps) down in the Timp Pass, near where the Ramapo-Dunderberg, Timp-Torne and 1777 trails all come together. Tenters might prefer that one to get out of the wind. (Even the rangers haven't been able to tell me whether that site is lawful; the rule is, "camp at established campsites only," and nobody seems to know for the permanent sites that don't have shelters whether they're "established" or not.) Of course, that wouldn't get West Mountain's great view of NYC.