In reply to Fenda:
Couple of option available to you;
Aviemore is the best bet if you want to get stuff out of your days, there is a good bus service between the town and the ski center for the skiers which you could utilise. The last one down is around 5:30pm I think and the first one up is 8:00am or there about. This should give you a good window of time for getting stuff done at around grade III, and you're spoilt for choice in the Northern Corries.
To get to Fort William from Aviemore, you need to go via Inverness which will take the day but regular services every day. Either that or you can hitch across as it's a busy road.
You can walk up to the climbing on the Ben from Fort William via the Smelter but it's not ideal, there is a bus service which will drop you off in Torlundy which is about 10 minutes walk to the North Face Car Park. Harder to catch the bus on the way back but never difficult to hitch a lift back to town or get a taxi if really stuck.
Either that or get a mate who has a car...