Webcams will give you some idea but unless someone’s been on that section recently, I’d give the folks at Cumberland Trail Connection a call. That shop is right on the trail by the Crabby Pig in Cumberland and they should be able to give you a good idea of the trail conditions before you make the drive.
Not sure how I missed this post but...
The past few years I’ve done quite a bit of riding on the section you mention. If the trail is clear enough to ride in Ohiopyle, it’s usually good from Connellsville to Confluence.
Now for up the mountain toward Meyersdale and Big Savage, I usually check some web cams to see how deep the snow is. This one and these at PennDot usually give me a fair idea of how much snow is laying down.
This winter however, it’s been tough. But studded tires help.
I used both rear panniers and a medium-sized trunk bag for the two times I've ridden the GAP/C&O trail. Considering you'll be staying overnight at B&Bs and don't need tents or sleeping bags, that should be enough to carry your clothes and other gear with room to spare.
I have a Topeak rack with a Topeak MTX trunk bag and Ortlieb panniers. The Topeak racks are less expensive than something like a Tubus rack, and I really like Topeak's MTX rack mounting system for the trunk bag - very secure, and super-easy to take off and put on.
My rack is the Topeak Super Tourist Rack - it has side wings to keep the panniers clear of the spokes, and lowered mounting bars for the panniers for better stability. I've used them on a half dozen tours with my Ortlieb panniers, and it's worked great.
Hey fellow Checkpoint club member! This is the one I used:
Obviously, given this isn't even close to a full set of fenders or even a full fender, temper your expectations. It'll keep stuff from flying into your face, but still expect your bike to be a little dusty and muddy, though not absolutely caked in it.
I wouldn’t say you need a u lock or anything heavy duty. A tiny zip tie combo lock is helpful to lock your bike if you run into a store or to lock your wheel while you sleep. Usually you can carry a bike up to your room if you stay in a hotel.
That lock below weighs nearly nothing and easy to fit on a bike for access.
QuickZip Zip-Tie Multi-Purpose Combo Lock 2 Pack https://www.amazon.com/dp/B082TGBTWR/ref=cm_sw_r_cp_api_i_DdMAFbWVN2ZE1