No need to take your canoe across. Just before you get to Pine, you should see the spur trail. Make sure to see upper set of Falls also.
Yes, you can leave the canoe at the beginning of the portage. Yes, it's long, at least 3/4 mile. Some ups and downs, some switchbacks.
I recall a trail from the portage to the falls.
also in the area, but others will have to give location, is the ruins of a cabin.
You can get to the falls from that portage. No need to carry the canoe over and back.
If I were to stay on Canoe or Alder Lake, I would head up to Johnson Falls at some point or two. It is a very long portage from Canoe to Pine. Do I need to bring my canoe to Pine lake to get to Johnson Falls, or can you go directly to the falls from that portage?