Hi Bob -
I’ve just got back a day or two ago from Glencoe. We travelled through or into Fort William often during our several days stay there. Fort William gets poor reviews, but I like it. It is, as others have said, pretty much a working town but it is an ideal jumping off point for several more popular destinations.
Including Ben Nevis, accessed by a short drive out of town to one of several car parks are in Glen Nevis.
The route you will most likely follow is ‘The Tourist Route’ which is well trodden and maintained and which is a safe option up. There are huge cairns on the way up nearer the summit marking the line of direct descent in bad weather (i.e. some are not directly on the path) as there is a risk of falling off the mountain - sadly as happened on the north face while we were there, with fatal results - if the correct route isn’t followed.
A more challenging ascent is via the Carn Mor Dearg arête, but this involves traversing a narrow ridge and a rock scramble to the summit and involves much more arduous hiking so you need to be a) much more than a casual walker b) comfortable with exposure and c) competent at route finding. The euphemistically named ‘Tourist Route’ is by far the most straightforward and ‘easiest’ ascent.
Be warned though. Ben Nevis has it’s head in the cloud for most days of the year - the summit is clear on average only twelve days a year - and even in summer can it can be bitterly cold on the top. I have been up in May and June of different years and have walked the final stages in poor visibility and snow. The fact that UK mountains are not particularly tall in the scheme of things does not mean they can be underestimated. Even if you set off in shorts and t-shirts at the bottom, it’s rare that you won’t need full body cover, waterproofs and hat and gloves on the top. We once set off in September in really warm conditions in t-shirts and shorts and on the top I was wearing every spare item of clothing I had taken with me. I even borrowed my wife’s spare mittens! By the time we got back down, we were back in shorts and t-shirts, so make sure you are prepared. You’ll see plenty of people on the way up who are hideously under equipped but it doesn’t mean you should risk it - it sounds like overkill if all goes well, but when it doesn’t.....
It’s a wonderful hike up, just take sensible precautions and I’m sure you’ll have a great time. If the weather is half decent you’ll get fabulous views in all directions! Fingers crossed!