Skyline Drive (Shenandoah NP) in VA

Good idea.  I'll bet it's beautiful up there.  Check the weather before you leave, and at your one third way point.  Small change in the weather in valley can mean a big change toward extreme conditions up on top.

I've ridden about half of it, from Front Royal.  The climb going in from Front Royal is epic.  From 600 ft elevation to 2000 ft elevation in the first 4 miles or so.  Another 600 ft up in the next 10 miles.  Be sure you have a low gear (28 or 32?).

Doing an up and back would be nice.  If you go too far, at least it's downhill on the way home.  If you get caught in a rain shower descending at speed may be cold and slippery.  If it's cold, the air will be dry, so take enough water.  I'd dress for 10F colder than you think you need.  You can always unzip or take off your neck warmer.

Don't count on your cell phone.  I seem to remember mine worked in a few spots.  There are probably payphones outside at the visitor centers even if they're closed.

Good advice; thanks!

I was planning on starting at Swift Run Gap off Rte 33.  I don't think there is quite as epic of a climb there, but it's pretty much all climbing or descending... not too much flat.

I will bring arm and knee warmers, wear an extra layer under my jersey, and also carry additional layers.  Gloves, skullcap, and tape over the vents on my shoes.  The weather looks like it'll be in the 50's later next week so I think probably 40's on the mountain.

Good point on the cell phone; I would prefer to ride with someone but don't know anyone in the area that rides.  Plus it will be mid-week so that's another limiting factor for riding partners.  Worst case scenario I will just establish a check-in time with family and hope I get service at some point leading up to that.