Yout temps are on target, 60's are possible. Up off the lakes, in the sun, you'll get sweaty. I was very hot when I did a late fall trip. Water management is a challenge.
Looks like there is a weather station on Clearwater, although the forecast is for Grand Marais:
https://www.wunderground.com/personal-weather-station/dashboard?ID=KMNGRAND16
Have you been on the BRT? If not, its a pretty rugged trail. The campsites are easy on your first leg, more challenging around Rose. The northeast site on Parttridge is nice and sunny facing the south, on a rock ledge. The eastern Rose site on the lake is nice, and that northern most site on Daniels is lovely, but both are pretty popular. If they are both filled you have to back track to the middle one on Rose that's up on the trail (yuck) or go several more miles to one on Clearwater. Two great overlooks on the part near Rose. Fantastic overlook just past the spur trail that goes to Clearwater, a good day trip.
To cut down the mileage, you could start near Mayhew Lake instead. The trail is a bit overgrown there, but easy.
Daniel