Myself and a friend paddled the Big Presque Isle River yesterday (April 22, 2007). What a blast! The hydro-metric primary water level was listed at 1.3m. At this water level the majority of the river was running at a class 1 and several portions at class 2. We were unable to pass safely under the Brunway job-site trestle with this high water level. A short portage and we were back at it for the fastest and best portion of the run.
Prior to starting the run, numerous locals informed us that a "swim" was guaranteed. Luckily for us (and help from my Hellman Prospector) we managed to finish the run swim free! Granted we were soaked and did collect enough water to fill the canoe about a 1/3 full.
I would strongly recommend picking your line on the bottom portion, prior to running. This can be accomplished at the take-out vehicle drop.