If it is still is too expensive to go to Canada, difficult to reach parks, there are no camping sites, etc., we can imagine other backup alternatives, plan b. For example to fly to Seattle and see parks around, or to Denver and see Rockies national park there, and maybe go to Yellowstone and Grand Tetons. We have been to Seattle and Denver but could go back, cheaper flight ticket etc. Do you think we are better off to book tickets and go there or other places in North Amercia? I guess Yellowstone and Grand Tetons could be difficult too much of a popular and tourist season at that time?
Unfortunately Yellowstone and the Grand Teton's will be just as crowded during this time. Backcountry Permits for places like the Teton's opened in January (maybe slightly later this year due to the shutdown). While they do hold back a few walk up slots (unlike Parks Canada) they are extremely hard to get. When we did the Teton Crest Trail in 2016 (we had booked in January), there was a huge line up for walk up permits (several folks who had been waiting since before dawn), while everyone managed to get a permit to go somewhere, some of these weren't for very desirable locations.
While there are places like the Bob Marshall Wilderness in Montana, or Jedediah Smith Wilderness in Wyoming with many, many, options for random camping. You'll be encountering the same kind of challenges as you would with the places like Wilmore listed above. Many of the more remote, less busy locations are only going to be accessible on gravel roads.
As folks have mentioned, the time you're looking at is the absolute PEAK of the summer vacation season in North America. Car rental agencies, hotels, tour operators will all be charging their peak season rates regardless of where you go. While it would be great to be able to just show up, meander around, explore and go where the winds take you, it's really not possible. If you don't plan, you'll likely be disappointed as you find hotels booked, campgrounds full and permits unavailable. I remember as a kid (before public campgrounds really took reservations) getting up before dawn so we could arrive at the campground as early as possible to line up for hours, waiting for sites to become available. My parents, walking around sites, checking tags, asking if people were leaving and setting up chairs to wait for them to pack up. In some cases we had to drive 100km to find an available spot.
I'd strongly recommend deciding on a location and starting to reserve sites and accommodation. With Alberta Parks 90-day booking window you still have time to look into and book front country sites, obtain backcountry permits (for non-random) and research random camping locations. There is lots of great camping (and backpacking trips) in Peter Lougheed Provincial Park (just not random camping) and through Highwood Pass (all on paved roads). Lots of neat places to explore and camp along Highway 22 (which is also paved). I'd still plan for a few days in Banff to see all the popular spots, but you'll either want to book a campground (if you can find one), or hotel (which isn't going to be cheap). Canmore has some options, not sure the summer rates at the Stoney-Nakoda Resort, but we've stayed there during ski season and rates were reasonable.
If you choose Calgary, I'd recommend the following
- Book several days (or even a week) at Elkwood Campground (Peter Lougheed PP) - Permit required. This is a front country campground, paved, and there are many day hikes are within a short drive.
- Backpack into Three Isle Lake and Turbine (Peter Lougheed PP) - Permit needed - Nice alpine lakes on the continental divide
- If you're ambitious, look into Backpacking Northover Ridge (Peter Lougheed PP) - Permit needed - Ridge walk along the continental divide, many claim it as one of the nicest backpacking trips in the Rockies
- Drive through Highwood Pass through Longview and onto Highway 22
- Check out the Bar-U Ranch on Highway 22
- Camping around Oldman and Beuvis Lake (not sure which of these might be on gravel)
- Check out the Frank Slide on Highway 3
- Visit Waterton (see if you can find a place to stay or camp)
You can put a few days in Banff at the beginning or end of your trip
As an aside Banff and Yellowstone get 4 million visitors per year, Jasper and the Tetons get 2.5 million per year
Hope this helps