Well just back from Africa with my Aquagear thingummy and drank from some very yucky rivers in a minor emergency whilst on a boat in the middle of the Luangwa river amongst other places and it tasted so good very clear saved some lives!
I don't suppose you where in Coire Gabhail (hidden valley) where you? I was up there watching a pine martin from the top of the big boulder in the glades there. Sounds like a Pine Martin except the narrow tail bit.......
There is a lot of choice from Glen Nevis that would be relatively straight forward doing one hill at a time. It's often doing more than one mountain in that area that involves crossing narrow ridges with the odd rocky step.
Sgurr an Iubhair - demoted to Munro top in 1997
A good easy route that takes you to a high point on the Mamores ridge. Start just up the road from Achriabhach Car Park in Glen Nevis, on a good track which goes all the way to the col beneath Sgurr an Iubhair through dramatic scenery beneath Stob Ban. Then rougher going to the summit.
I wouldn't recommend going to any of the other summits from there because some of the ridges hold nasty surprises in winter conditions depending on your confidence and experience.
Ask your guide on Saturday about it as well. What are you planning to do with them do you know?
Mind how you go...
Oh and it's on OS Sheet 41. !5 minute drive from Fort William?
It's a wonderful view point on a good day and a good walk on any other!