Maybe I should expand a bit on what I found this morning. Some bits of the Pennine Bridleway were clear including the steepish descent of Royche Clough and up the other side, but more than 50% of the distance from Rushup Edge to South Head was deep in heavy snow, so that rather than going through a number of the gates, you could just step over the top. Also there are a couple of smaller cloughs before you reach Royche Clough – at these, the snow had corniced and I guess was about 10ft deep. Yet the fields are pretty well clear. The snow has drifted into the track between the walls. It is possible to get along the track, but for more than 50% of the time, you'd be carrying or dragging your bike – no fun at all, particularly with a large group. I'll try to post a few photos I took with my phone if I can get my head round the technology.
My suggestion would be to do the proposed route as far as the Pennine Bridleway. There is plenty of snow at the gate onto the PB, so you could have a look from there. If it's very slow going over Lord's Seat, head back to Barber Booth via Chapel Gate, or by road via Mam Nick. If it's been reasonably easy over Lord's Seat, extend the route into Pin Dale or Cave Dale, or even both. I don't think it's worth going for a completely different area at this short notice.
Let's face it though, the conditions aren't good for a high level ride and some people may prefer to give it a miss.
As I (and of course Sambob) live about 20 minutes away from Edale, we'll come over anyway and if we finish up doing a shorter route, so be it.