Have done each of those areas last summer and the summer before that.  The only beaver dam problem I know is from the unnamed heading north into Kahs.  The first few hundred yards heads through some shin-deep muck through the meadow/swamp on the east side. 

I noticed at least a couple more beaver dams heading from North Bay into Isabella.  I left PP as a solo that morning and by the time I got to Isabella I was quite beat...never made it through Side till the next day.

That 3-portage creek route from Side to Sarah is more scenic and easier in my view than the tough up and over portage into Sarah. 

The portage from Point to Isabella is a 24 rod portage that is fairly straightforward.  There's some nice smallie action in Point btw.

I've stayed at the campsite RC on Sarah.  Very nice and good windbreak from a west or north wind.    My favorite site on McIntyre is LH.  Good views to the east, great sunrise in the morning, laker fishing as you head north from camp, and a message cache to the north in the woods.

Hope this helps you out.