While Banff and Jasper are busy, the Ice Fields Parkway is one of the very most scenic roads in the world and a delightful experience regardless. Seeing Banff town and especially Lake Louise is harder; camping unless one has reservations well in advance generally means overflow camping (i.e. a parking lot with a fee and a porta-potty), and you'll definitely be best off taking the shuttle bus services rather than trying to drive around and find parking in the villages/towns. There will be many people around. The scenery is spectacular, though. If not this trip, plan to see it sometime if at all possible.
The Trans-Canada highway between Camloops and the Banff area is a lovely road, too, going through (Canadian) Glacier National Park and Mt Revelstoke National Park.
Getting to Haines (or Skagway, or both) by road is a long way around, not really good if you're pressed for time. The Taylor Highyway to Skagway is another very scenic drive, with surprisingly varied topography and flora.