In reply to redrook:
Eh?! From the visitor centre in Glen Nevis you'll be following the normal route up, the bog-free (stony) tourist path. If the summit is the priority then just walk all the way up this, it's the most straightforward way to the top.
If there's time you could then do the CMD Arete in reverse, as you've said. Then follow the rough trail downhill from Carn Beag Dearg at the northern end of the ridge, down to the allt a' mhuilinn path. Cross the burn, slog up the bog to Lochan Meall an t-suidhe, then you're on good paths all the way back down to Glen Nevis.
It's also possible to cut downhill early, from Carn Dearg Meadhonach to the CIC hut kind of area, but a tolerance for descending very steep scree and grass slopes is required. From just downhill of the CIC you then follow the obvious traversey path under Carn Dearg, which is quite a dramatic way to walk out from the corrie. Up and over past the lochan and down the tourist track to the car park...
...unless you meant the North Face Car Park? In which case yes, you'll be ascending the soggy stuff to the lochan. I've never been up it but other than starting the day with possibly wet feet I don't imagine it would be that bad. It's definitely not the quickest/easiest way to the summit however.