I'll just get things started by tossing out a few things...
At the top of the Blue Ridge Pkwy is the Skyline Dr. in VA. It's about 100 miles long, and is similar to the BRP, except that you have to pay to ride (and it's patrolled by federal LEOs, so you don't want to get a ticket there). Beyond that -- still in VA -- I don't think you're going to find any single scenic road that goes all the way north to NY.
Keep in mind that the BRP is very scenic, and lots of pullouts, but the speed limit is very low (something like 35 in most places). I travel to and from Albany, NY (about 150 miles north of NYC) to and from Asheville, NC, to visit family. Often going home, I'll take I-81, but that first of two days I'll do a chunk of the BRP (say, 100 miles), skipping different parts of I-81.
So, one point here is that you'll need a lot of time to travel all or even most of the BRP.
Speaking of time, a lot of people don't realize that NY is over 300 miles wide. And that Niagara Falls is on the far left, and Maine is way past the northeast corner. So -- not knocking Niagara Falls, as I've been there, and it's worth seeing -- but for that sort of loop, you're also looking at a lot of time. You CAN get across NY on nice backroads, skipping the east/west superslab, via, say, Rt 20, but, again, you're looking at a lot of time.
A couple of years ago, my wife and I rode north to the Gaspe area in eastern Canada, straight north to Montreal and turn right, and then rode home via New Brunswick and down through Maine. I think you can lobster pretty much all the time, but the ME folks will have to chime in here.
You didn't mention how much time you have, and I think that's the first thing that needs to be taken into consideration.
2012 XCT (SOLD)
: HeliBars; Centramatics; PC-V; Lloydz air filter; 11" Madstad; Rivco LED mirrors; Doran TPMS; Stebel horn; Motolights; CustomLED trunk flasher; KewlHeel shifter; CycleOps trunk rack; BeadRider seat; Vibranator bar ends; Passenger grab handles; Powerlet outlets; Handlebar RAM mount; RicZ laydown plate; Brukus SaddlebagSecure; 14" flexible antenna; RAM cupholder on trunk; shock Schrader valve relocation.