There's a Four Points Sheraton at Canada Olympic Park that is right on your way out. There's very little between Calgary and Canmore, mostly due to the Stoney Reservation.
https://www.marriott.com/hotels/trav...b-83b6a417f6fe
Banff Ave. is great, and there's also a robust transit system that goes from the Rimrock/Gondola/Hot Springs all the way down to the end of Banff Ave, or alternatively the Banff Springs and down.
You can generally get a decent hotel for under $200, including the Rimrock. Banff Springs is about the only place that is the exception. Although I highly recommend their Sunday Brunch. Try trivago or a similar site. October isn't really ski season, it's actually the end of shoulder season, so you should be able to find a deal.
Check with the Parks Canada website as to road closures, as it's right around the time that things are shut down for the winter (eg. the road to Moraine Lake)
Your chances on the northern lights are about nil, due to the southern latitude and mountains.