Yep, I use hepa equipped vacuums for all of my vacuuming needs, and the overall level of dust in my house (and darkroom) has gone down significantly. Now if I can only get the dog to vacuum himself after he's been playing in the yard, I'll be all set.
The vac has a vacuum port and blow port. To keep it simple all you really need to do is put it in the darkroom with a filter installed and turn it on to move and filter the air. I plumbed a light tight port through the darkroom wall using 2" electrical plastic conduit and draw air from outside to maintain positive pressure. It does get warm but I only print in the winter anyway because of temp control issues and FLYING BUGS!
Shop vacs are pretty noisy, here's an alternative from the woodworking world that should be much quieter. Jet tools sells a similar unit. Cost is probably higher.
Or get on of the room Hepa filters. They do a great job in a small space like a darkroom. I combine this with vacuuming with hepa vac, and this works well.