Lots of good info on Banff so I will stick to the jasper end. We usually camp there one weekend each spring and I have been trying to see new sites each time and not repeat some of the classic. In my opinion malign lake is not worth the drive. It will take you the better part of half a day to just get out there and back. Last summer we hiked old fort point and valley of the five lakes. They were both great. We really loved the valley of the five lakes. Edith Cavell was closed the last few summers, so not sure if they will be open.
We love the whistlers campground in jasper, but sadly it is closed this summer to log out all the pine beetle killed trees. Wabasso is great but a bit further from town (20 minutes) and only loop D is powered. I have heard good things about wapiti, but haven’t been there. I prefer mountain campgrounds that are farely open, so I can enjoy the view.
If doing the jasper tram the tickets are sold for specific time slots. You can buy the tickets online and then just head up for your scheduled “flight”. For parking in the jasper townsite there is an RV lot that you can access from highway 16 halfway through town that is open for cars also. It is on the opposite side of the train tracts, but has a pedestrian underpass and it takes you to the main part of the little downtown. Much quicker then Fighting for street side parking.