Hi Canadave:
We have actually done 4 different routes now, & just got back 3 hours ago from our latest trip. Here are my thoughts:
We're in Whitby, so we're about 4 1/4 hours from the Windsor border,
2 hours from the Niagara Falls border, & 2 3/4 hours from "Kingston" border.
I75 through Windsor: safest for weather, & most places to stop. We took it home this time. Total kms from Orlando: 2,360. We always do this 1 way each trip. (Sidenote: In the past, we have gone through Sarnia as we have had relatives to visit just north of Detroit. Today we decided that we definately shaved off a good chunk of time by going through Windsor...family has now moved up past Sault Ste. Marie area.)
I79/I77 through Buffalo: Did this route 3 years ago, late Nov. Pretty route, only 2,300. I think we're most likely to avoid this route during heavier snow times. Also, exits are much farther apart. CAA is also recommending not using the "short cut" in WV (go through Charleston instead?) because of the steep hill or something. We found the drive around Lake Erie to be kind of frustrating...you feel like you're so close to Canada, but so far!
US15 through Buffalo, to I81 at Harrisburg, to I77, to I95. Did this on the way down late Nov 2002. I recorded 2,700 kms, but we did MANY different side trips & took 5 days to go down, so you can't use this for comparison! I81 from Harrisburg is actually in the valley, not on the mountains, but I think there's still a good chance you could get a good storm. Very pretty, with lots of side trips available.
I81 through "Kingston", to I83 at Harrisburg, to I95 at Baltimore : Did this route down this time, 2,540 kms. We enjoyed this route, and even though it was longer kms, it wasn't longer time-wise. It seemed that alot of the hwy was 70mph. We didn't have as much trouble finding places to stop as we did on I77/79, and while the first day to Hershey PA was "mountainous", it was NOTHING like what you go through on I77/79. We chose this route this time because (we like to try new routes and) we figured if there was bad mountain weather we'd miss it.
My husband, who does all the driving, prefers I77/79 for the landscape. However, if faced with bad weather, we'd choose either I75 or I81 over to I95 to avoid the major mountains.
I hope this helps! Have a wonderful trip, & I hope you have weather as nice as we did.