Red Bus Tour , Kayak at apgar village , whitewater raft, trail of the cedars is a super easy hike. Hidden lake trail isn't hard but I wouldn't say it's easy but it has amazing views and we saw several mountain goats and a few other small critters- and I'd say highly worth it. Parking can be a PITA but you'll drive GTS road up and it's gorgeous.
If you're up for a drive (some of it unpaved) check out polebridge mercantile and bowman lake.
Just be mindful of which areas you need timed entry to etc. (bowman lake, GTS road etc) but if you're doing a bus tour for example it should cover the entry.
Whitefish is a cool town to check out , you can go to the resort and do the gondola up the mountain.