A nice road is the road from the Soo out to Searchmont - nice fast sweepers with great pavement.
Check out the Terry Fox memorial in Thunder Bay if you have a chance
If you're talking about the 556/Ranger Lake Rd. You need to be extremely careful when you get about 30-40 minutes down (a little passed the Searchmont turn-off), the road has been shut down in the past for severe frost heaves and I've ripped the bumper off a cavalier out there too. They're not always signed and sometimes are pretty nasty. Mid-summer they should all be at the very least signed though.
I say this because it's VERY tempting to just continue since the road is so much fun.
Also worth noting that as I remember there is NO gas on the entire 556, so plan accordingly. The 556 in its entirety end to end is around 110km if I'm not mistaken. If you do end up making time for a quick Ranger Lake Road/Hwy 129 run it is OODLES of fun with terrific scenery. The 556 becomes an extremely technical road though for about 2-3 hours worth of riding. I personally wouldn't try it without 50/50 tires and a long suspension to account for the random parts that are hard packed dirt/gravel. It'll go paved to that to chip seal to old pavement etc. Ripping down that road with AWD and a turbo 2.0 was almost as good as riding. And bonus, no OPP ever. Never ever ever. They won't go down 556 unless there's a 911 call. It's too remote for their radios to work and traffic is so light/rare they won't ever write tickets either. The 129 is a completely different story.
A fantastic day trip is:
SSM north on 17 to Heyden
Exit onto the 556/Ranger Lake Road
Follow that for about 2 hours (110km or so) and it will end at the 129
Turn right, ride down to Thessalon, fuel up.
Turn around, ride the entire 129 up to Chapleau now that you're not worried about fuel!
Fuel up in Chapleau, have some lunch, ooh and aah at the scenery.
Ride south to the 101, take that Westbound to Wawa (pretty dull riding wise I apologise, but it's freshly paved and the scenery is nice so there's that.
Stop in Wawa, repeat steps for Chapleau.
Either ride south back to the Sault to rest up and do the Superior loop in reverse (start in Sault Michigan and come back around to Canada since this is a 12 hour day) or head north to continue the Superior loop!