Im not a strong hiker, I have bad knees, but even though I was sore for a day or two afterwards I was able to complete this hike and Im glad I did. I went when there was snow on the ground which probably made it harder but made the payoff very cool in my opinion, the waterfall was a giant mass of snow and ice. There are a lot of great views of the surrounding mountains throughout the hike as well, you will definitely realize just how high you are.
I wouldnt recommend bringing a dog unless theyre very calm and used to hikes, the trail is fairly narrow and I would be worried about them falling too frequently.