Some attractions are close to the road: Giant Cedars Trail and Hemlock Grove Trail. There you can see very old, large red cedars and hemlocks. The oldest are 300-350 years old. Afterwards I drove to Rogers Pass Center to ask about details on the trails and to get a recommendation.
The women at the Rogers Pass Center recommended the trail to Abbott Ridge (besides Perley Rock and Sir Donald) - a very good recommendation. The first 2.5km to Marion Lake took 50min.After 2.15h (including a few stops), I reached the end-of-trail sign. The view is really very scenic. On the left, there are the Illecillewaet Glacier, Sir Donald, and on the right, another valley with Loop Brook and the ridges, glaciers, and peaks behind.
The women at the Pass Center had said that I should be nosy and that the path goes on.
So, I went along the ridge to Mt. Abbott (2454m) and the hike became an easy scramble. The way up to Mt. Abbott required a little bit of climbing, which was worth the effort:
A great scenic view from the top - also into a "hidden", hanging valley covered by a glacier. Time for lazing around on the peak for a while and enjoying the breathtaking view. It took approx. 2h to return (passing many people ;-)
p.s. The rocks had sharp edges. You might consider using gloves.