Most grades on the Parkway are a moderate 6% or less. But there's a few climbs where part of the climb gets to a quite steep 8-9%. Your Madone with a triple should be fine. You probably have a 30-27 low gear on it, good for the steepest Parkway grades. (That's the equivalent of between a 34-30 and a 34-31 for bike with 50/34 compact cranks.)
For me, climbs on the Parkway are nothing like the local 300 foot climbs. A 1000 foot climb on the Parkway seems way easier than three 300 foot local climbs. The Parkway climbs have a steady grade, and there's all kinds of scenery, from distant views to woods to rock walls. I know it's a long climb, so I slow down to a sustainable pace, and I'm at the top sooner than I expected.
It's the side roads leading up to the Parkway that can get very steep.
Moses Cone Craft Center to the Linn Cove visitor's center
. See my ridewithgps map
. It's just 22 miles round trip.
This is one of the best rides on the Parkway, a must-do route. It was the first ride I did on the Parkway, years ago. Before I got there, the big climb intimidated me, coming from SW Ohio. But it's a steady grade, so I just enjoyed the views, rode at a sustainable pace, and got to the top easier and sooner than I expected. The return downhill was fun. There's no sharp turns or cars pulling out of side streets, so it's safe and enjoyable.
It starts with a downhill, then 3 miles of gradual uphill to the big 800 foot high climb to the Linn Cove Viaduct
. The climb has great views all the way up, and there's some scenic overlooks to stop at on the way up. Then you cross the Viaduct and continue on to the visitor center. On the way back, you have a 5 mile downhill, then end with a climb back to Moses Cone.
Little Switzerland to Linville Falls visitor center
. One-way route map.
I haven't done this section of the Parkway, but it looks interesting.
This route starts in Little Switzerland and rides along the mountain ridge top. There should be good views all along this section. This part is fairly flat for the southern Parkway, with the biggest climb just 270 feet. A nice mix of climbing and descending.
The big climb is 1100 feet in 3.5 miles. The grades are mostly 5-6%, so take it easy on the climb. You could turn around at the top at the 13.0 mile mark (or sooner!), or continue down the other side to Linville Falls.
North from Blowing Rock
. Here's a one-way sample route
. It starts at the next high overlook north from Moses Cone, to avoid climbing back up at the end of the ride. (I haven't ridden this exact route.) Near the turnaround, after crossing US 421, it heads uphill. You can turn around at the overlook at the 16 mile mark to start the return route with a downhill. Or even turn around at the top of the climb at the 12.7 mile mark.
I think this goes almost to E B Jeffress Park, which has a picnic area, but I don't know if there's water there, and I'm not exactly sure of it's location on the route map. It's probably a half mile onward from the route's turnaround point.