I went for a trip there around the first to middle of September IIRC and a week after I left it was snowing. Figure it to be cold and most likely snowy. Check the average temps for the time of year below at the link. Have fun driving in it if your from S. Calif.
Banff's a nice town. Alot of young people in the summer and alot of Aussie's for some reason? Moraine Lake and Lake Louise are very pretty. Jasper would be nice but the roads will be "forget about it." Snow on the mountains tops should look nice. Try some shots around the Hotel at Lake Louise. Also go to the ski lodge up the mountain from there.
The average snowfall for Oct- 20cm, Nov- 32cm Average temps for Oct 4.4 deg C ; Nov -4.1 deg C. You might consider going skiing?
Just plug in Banff, etc. The real page link was extremely long.