I am starting to plan a trip for 2015 (and I know it's late to get accommodations in parks, but I will keep calling and book outside the parks for now. We can start or end in Banff and have saved about three weeks for this trip. My first question is, what kind of weather (or weather-related problems) can we expect in these areas in late May or early Sept.? These are our favorite times to travel. Thanks so much.

I would be more inclined towards September. The weather will be more reliable. It would not be at all unusual to run into quite a bit of snow in the higher elevations (and lower elevations) in May. Also, if you're thinking of visiting Glacier Nat'l Park on your way to Banff, Going to the Sun Road will certainly be closed.

September is on of my favorite months in MT. It's usually beautiful, and the parks won't be as crowded as they are in during the summer months.

I'd skip Banff and visit Glacier NP. You should still be able to go over the Going to the Sun road in early September.
May is too early for some of the roads in Glacier.
Glacier is every bit as beautiful as the National Parks in the Canadian Rockies IMO.

September. Check out the opening/closing dates of facilities in Yellowstone and decide if you would rather start or end there.

Many parts will be closed in May -- definitely September.

Glacier is beautiful, but it covers a much smaller area than the Canadian mountain parks. To get that close to them, and not make the effort to take in at least a portion of the Canadian Rockies, would be a big oversight, in my view. There is too much there to see, to just skip it, for the sake of a few hundred miles. Early September is a great time to go, and snow is a real possibility, but it usually melts within a few days.

Thanks very much. I prefer September, myself, so Sept. it will be. I will do some more research and get back to you all with more questions.

Remember there are always cancellations in the park lodges and the best way to find out is to call rather than check online.

We were in the Tetons this past August - early September and it was spectacular! Be sure to check out String Lake and Leigh Lake, which were spectacular, especially in the early mornings. This is a good reference for hiking trails in the Tetons.

http://www.tetonhikingtrails.com/grand-teton-trails.htm

The only negative (for us) was Moose-Wilson Road. We did not have a 4-wheel drive and the unpaved portion was not driveable for our car. Since we stayed in a condo on Moose-Wilson we had to drive around through Jackson to get into the park.

Thank you again. Will definitely visit Glacier as well as Banff. Thanks, wave725 for the driving tip. I have rented 4wd out west before and felt more secure on the unpaved roads. I will also keep calling, as I myself had to cancel a month before a planned trip last year to Bryce and Grand Canyon North Rim.

While Glacier is beautiful, you have to work a bit more going on hikes to see the scenery at its best.

There's a lot of roadside scenery in Banff & Jasper.

A new question: If I can't get lodging in Yellowstone itself, what is the next best, closest place to look for a B&B or hotel?

Depending on where you are coming from, try Gardiner (north entrance) or West Yellowstone (west entrance).

Will do. We are planning to be there for 4 or 5 days. Would it be best to try to find two different places near different entrances, i.e., one in Gardiner and one in West Yellowstone?

I would just stay in West Yellowstone.

We've had a change in plan. We think we are trying to do too much, so have narrowed our trip down to Banff and Jasper over 12/14 days. I will switch over to the Alberta Forum for advice. Thanks so much for the above. We would like to do Yellowstone and Grand Tetons next fall. We think we will appreciate all of this more this way.

Good plan. Less is more. Have fun!