Blue lake road in Minocqua and the road from Woodruff (off highway J) through the Rainbow flowage to Lake Tom is a nice ride. Highway J all the way to St. Germain is a hoot too.
If you get to Lac du Flambeau highway D? I think that runs from 70 to 47 is a good twisty.
(I may have grown up in Woodruff and could give you a TON of road names to hit).
^This is county E
If you're interested in a day trip, a good ride for you (that hits every one of these roads) would be:
Head north on Lakewood to D
Take a right on D and follow that to 47 (Just south of Lake Tom)
Take a left on 47
Then a right on D (Just before you get into Lake Tom)
After about 3 miles, D turns right. Stay straight on E
Take that to J and then turn right
Follow J to Hwy 70 in St Germain and then turn left
Go through St G. and continue straight onto 155 (70 turns left)
Follow 155 to the town of Sayner and then turn left on County N
Follow N to M and turn right
Follow M through Boulder Junction and continue straight on K (M turns right)
Follow K to W and then turn left
After 2 miles you'll come to HWY 51
Turn right and ride north through Mercer
Just north of Mercer, take a left on FF
FF turns into F and goes to the town of Butternut
In Butternut, take a left on 13
Follow 13 to Park Falls and take a left on 182
Follow 182 to 47 and take a right
Follow 47 through Lac Du Flambeau and take a right on D
Follow D to Hwy 70 and take a left
After about 6 miles, you'll see a little bar called the Black Bear
Go another 1/2 mile and turn right on Mercer Lake Rd
After a while, Mercer Lake Rd turns into Blue Lake Rd (on a left turn that feels like you're just following the road)
Follow Blue Lake Rd to HWY 51 (just south of Minocqua)
Take a right on 51 and head back to Birch Lake.
I'm guessing this will probably be around 200 miles. There are several points where you can easily head back to make it a shorter ride. These will all take you straight back to Minocqua:
Follow 70 to the left instead of staying straight on 155 in St. Germain; then Left on 51
Turn Left on M instead of right after Sayner; then left on 51
Turn Left on 51 instead of right after W
Follow 13 to Hwy 70 instead of 182 and turn left
Stay straight on 70 instead of turning on Mercer Lake Rd
If you make it through Mercer and turn left on FF, about 5 miles down FF, you'll cross Lake of the Falls on the Turtle Flambeau Flowage. I highly recommend you stop here!
Typing all of this makes me want to just come up there and ride it with you!