Rushup Edge is definitely one to give a miss in the winter. It's nigh on impossible to even push up the first section. Although I did do it a couple of weeks back when it was frozen solid and it was ace.
Which is a shame, as Chapel Gate is currently one of the best descents in the Peaks. It's generally pretty quiet, and it's one of the few Peaks trails where you can see far enough ahead to go properly quick on a big bike. LOTS of fun. I really don't understand why so many people are afraid of riding (or walking for that matter) in the gullys. Given the choice of shitty, slippery, muddy, grass or nice grippy rock I know hwich one I pick every time. The last time I did went down I overtook a bunch who were fannying about in the mud and whose feet were about level with my ears when I went past. Sure there's some biggish drops, but a) nothing you *have* to huck, and b) that's what suspension forks and chunky tyres are for. And there's always the tarmac strips to ride down if your arms want a break (although not a brake as there's SFA grip...)
Anyway. All you have to do to miss out Rushup Edge is ride down the road a bit, then up the Sunken Road. (also a nice little challenge in either direction)
There's a few places worth avoiding in the Peaks in the wet, but there's plenty more paths that can be strung together to make a good all weather loop. I just wish there was a decent (legal!) off road route to link Ladybower to Stanage Causeway.