Something like Cascade, or something higher alpha like Nugget? Also, I'm planning to make the garden small in the beginning so there'll be room for 3-4 vines max. Should I grow one variety or can I do more in a small area?
If you like Cascade, that's what you should grow. That's what I grow. Admittedly I olive in prime hop growing country, but I've gotten up to 27 lb. off my single 13 year old Cascade plant. Be careful not to plant too many varieties at first, until you know what you've gotten into. Growing them is very easy. Harvesting, processing and packaging can be a real pain.
This is great advice. The varieties I would recommend: Cascade, Columbus, Mt. Hood, and Glacier. Easy to grow and versatile.