If you're doing Sarrail as a day trip from the Upper Kananaskis Parking lot, you are in for a fairly long day. The hiking and scrambling are fairly easy though, so it's doable for fit and fast parties. We did this trip on our way into the Aster Lake area for a few days of peak bagging the Kane peaks.
As part of our Elk Lakes backpacking trip, we took a day trip to Petain Falls. This is a pleasant and very easy hike, about 10km return. We also included the Elk Lakes viewpoint hike on the same day which made for a longer day and much more effort.
Signal Mountain is easily done off the Skyline Trail backpacking route in Jasper National Park. I would never do it as a stand-alone peak but it could be combined with an ascent of nearby Mount Tekarra via the Signal Mountain fire road from the Maligne Canyon parking lot.