There is a series of shorter portages that I have not gotten around to showing on the map yet. There are some comments about the portage vs. the series of portages if you view the portage details on the map. This one by sns is the most detailed:

"So the two previous comments on this one are now clear to me... There are two possible routes to get from Beartrap Lake to the Spring Creek/Beartrap River intersection, en route to Sunday Lake. I discovered this by presuming that the 1153m portage marked on the paddleplanner map (accurate to my eye as of September 2020) was at the outflow of the lake. If you look with any kind of care, you will see this is not the case. I should have paid more attention! It's in the next bay to the North. There is, however, a portage-paddle-portage-paddle-portage-paddle option (that's three portages for those of you playing along at home) if you go to the outflow of Beartrap, and find the obvious trail on the river left of the outflow. The three portages are much shorter than the long single portage of 1153m...perhaps 400m in total, and for the most part your route is right along the river. This is how I went to Sunday Lake, and this 'shortcut' took me, single-portaging, about an hour fifteen. On the way back I found the 1153m portage pretty easily, and singled that in 17 minutes. But if you are doubling or god forbid tripling, the 3/400m may be more palatable."

I also had someone email me earlier this year to clarify the route (again, I haven't put this one in yet, but I will sometime...). He sent me this map:

Generally, it is better to use the longer portage the comes out of the northern bay. The mistake most people make is the one that sns described - assuming that the longer portage is by the outflow. The short portage by the outflow is easier to find, so many people make that mistake.