I tried mapping directions from Apple River Campground in Somerset, WI to Northwood Shores in Rice Lake, WI but Google says "Sorry, we could not calculate biking directions from "Apple River Campground (Address)" to "Northwood Shores (Address.)" I got the same error when I tried to go from Northwood Shores to Eagle River Campground in Chippewa Falls, WI.

Does anyone know why? Is there a section of this route that's not bicycle friendly?

I switched my destination to Shady Rest Campground also in Rice Lake and it gave me directions there. It also gave me directions the opposite way. They basically cover the same roads. US 53 if I'm not mistaken.