There are lots of choices, from Banff the #1 wil go straight to Vancouver and is the main route. From Jasper take 16 west to #5 and then south to Kamploops and back on to the the #1. After you climb up through Kamploops you can take the Coquihalla which is 4 lane divided or continue on the #1, they merge back together in Hope. They are all good paved roads but the Coquihalla will have steeper climbs then staying on the #1 which is longer.
2004 Newmar KSDP 3353