Directions...
I grew up around St. Paul, so I know some of the roads there...on an AIDSRide a few years ago, we crossed the St. Croix at Stillwater, and climbing that nasty hill up into WI was a real treat! They had a guy in a TdF polkadot jersey standing about the middle yelling "This is MY hill! NOBODY walks up MY hill!"
FO is sort of the "backside" of Granddad. I've never come down the front side at more than 39, and after I saw a deer on the final stretch, I decided that self-preservation might be a good thing. FO, on the other hand, will allow speeds well over 50 MPH...the curves are broad and the road is mostly straight and smooth.
Technically, the road you want is called Bliss Road. It starts at the base of Grandad, taking off from the end of Main St, and climbs up past the park entrance to run along the ridgeline, with a few saddles. About 1/2 mile (or so) before it ends at Route 33 (a hill that will take you to South La Crosse, but rather busy), FO departs Bliss to the left. It's a county road, and fairly recently repaved. You drop like a rock, and you can follow FO all the way to Barre Mills.
The area is starting to get more and more built up, but it's still a great place to ride.
La Crescent is a very nice area, and getting across the bridge should now be easier, as there's a new one with a reserved bike lane (and they're repaving the old one, so there won't be as much problem with the gridwork). And then there's Trempeauleau!