Can anyone tell me if the creek/stream out of Slim Lake into Fat Lake is able to be paddled in early Spring?

I can't imagine it ever is. You're better off taking the portage.

No

Thanks.

If your goal is to travel thru Fat and beyond that Moosetrail portage from Slim to Fat is not faster then going thru North/South/Steep. We went to Tak lake last year and timed it going both ways 2x portageing. It was about 20 minutes faster going the long way. The first 90 rods of the Slim/Fat portage is a real dusie.

It's a big elevation change from Fat to Slim. Fat is higher, so the creek flows out of it and into Slim. But there's no way it's navigable.

Do you know about the unofficial portage between the two? We did it right after ice out last year, going from Fat to Slim, and it was not too bad under those conditions. But I'd guess it would be harder after green up because the flora is really pressing in on you. And going uphill would be much harder, though doable if you are good at portaging. I have a GPS track of it if you (or anyone else) is interested.

PPr shows the portage which is not maintained. As others have advised, the long way around is shorter and easier albeit with more portages.