I’ve been up Snowden twice this year. Once as a day trip, one as an overnighter, camping on the top.
If you go up and down in a day, definatly do the Rangers path. The route was published in the mag a few months back, and it gives you all of the route details in there.
If you’re thinking about camping at the top this is what we did:
http://bearbonesbikepacking.co.uk/phpBB3/viewtopic.php?f=8&t=1068
Best times to do it would be anytime over summer, when the evenings are going to be warm, as at that height you’re going to loose a lot of temerature, but more of waiting for a weather window when things are going to be calm.
In terms of gear, i just took a sleeping bag, mat, bivi, and a few warm clothes.
Glad i did it, but not sure i’ll be in a hurry again. Snowdens very used and it wasnt great getting woken by all the 3 peaks people with their headtorches and chatting at 3am, and out of all the bivi’s i’ve had this year, it was the least glamorous.