Here's the best way I can see doing it as a loop from Brent. I typically prefer a more relaxed pace but I think this could be do-able (I paddle tandem and single carry portages). All days end up being approx 5 hrs travel time (we're usually pretty true to estimates on Jeff's Maps). This is longer than we typically travel in a day but generally we're pretty lazy around camp so we could pick up the pace without too much effort. 

Brent Access to Cauchon for night 1 
Cauchon to Erables for Night 2 
Erables to Nadine for Nights 3 and 4 
Nadine to Rolling Dam Sites on the Nip for Night 5 
Rolling Dam to Brent Access

Thoughts? Advice? Insight?

Hey Claire, my fiancee and I did almost that exact loop last summer and it's a good one. A great mix of lakes - big and small, rivers and creeks - and ruins galore! (if that's your thing).

We did Little Cauchon, Erables, Nadine, Nipissing. Went in/came out at Cedar Lake.

Fantastic loop - just get an early start on Cedar - not only to beat the winds on Cedar itself but also on Little Cauchon (and Cauchon if you're going that far) because they can kick up pretty bad past 12 noon. (this has been my experience several times - always glad to be on a campsite before the winds make my day harder than it needs to be.)

The day from Little Cauchon to Earbles felt long, but its not so bad. The day from Erables to Nadine was pretty intense. The portage between Little Nadine and Little Osler is just out to lunch for insanity - especially if you're travelling south. It's doable (obviously) just plan some extra time for this day. Take advantage of the spring on the portage between Osler and Nadine. And great call planning for 2 nights on Nadine, not just for the travel the day before but it's a great lake to wake up, brew a coffee and do nothing on.

The Nip is fun. Campsites generally stink but there's the odd good one here and there.

I was on Nadine last summer as part of a longer trip: Cedar --> Catfish --> Hogan's --> Lake la Muir --> Burntroot --> Nadine via Nipissing --> Nipissing --> Cedar.

Nadine is definitely a unique lake with the clearest water I've seen in Algonquin.  It's worth the trip.  Keep in mind that the portages into Nipissing are a slog.  Also, the water in the Nipissing isn't the most appealing.  I ended up carrying a lot of water out of Nadine, and I don't regret it one bit....of course the portage out was all down hill.

If you're interested in a shorter loop you might consider Cedar --> Catfish --> Burntroot --> Nadine --> Cedar via Nipissing.  If you want the fastest there-and-back trip, it's probably the Nipissing from Cedar.  For my trip I was planning on spending a night on a site by the Rolling Dam, but all the sites on the river are sub-par.  I ended up going from Nadine back to Brent in one shot....I kept thinking the next site will be better.  If you can manage the distance you might stay at one of the better sites at the mouth of the Nipissing on Cedar, and try to get to Nadine in one shot.

Between Cedar and Catfish the Petawawa is no problem going upstream.  I haven't personally done the stretch between Sunfish and Perley Lake, but on my trip I was camped on the site next to the portage between Burntroot and Perley and spoke with a couple who came up the Petawawa from Catfish and they said it was fine.  The fastest moving water I experienced on that trip was on the Nipissing.

In terms of portages, the 2345m on the Petawawa wasn't as bad as I expected.  It's long, but the climb is gradual.  I found the 1410m into Nadine from the Nipissing to be much worse.

Great lake, enjoy it, springs all over those portages, don't be afraid to try!