In reply to mypyrex:
Had my last armful of poison on 15/8, then 2 weeks wait before 4 weeks of radiotherapy. Thereafter headed up to Ben Lomond on 15/10. I'd kept pretty active thru treatments and thought I was quite fit, but halfway up I found the going tough (also had less lung lobes than the last time was on a hill). At the top the plan was to come down the ptarmigan ridge but I ended opting for the easiest option of descending my ascent path that i was familiar with. All in all a great day but was way harder than I expected.
Your choice of route sounds a good one. I don't think it's with pushing yourself too hard while your body is still recovering. Foolishly I did several times when out running/plodding in the early recovery months and always ended up catching a bug/cold. I guess just take your time and listen to your body.
I hope you have a cracking day on Snowdon. I'm sure you deserve it.