O'Brien Road (that turns into Vander Karr Road as one heads east) is one of my favorites. It crosses through farm fields, past conservation land, and over the Nippersink Creek in the north part of the county between Alden and Richmond.
Thayer Road is another of my faves, going from Alden Road in the west to Greenwood Road in the east, passing farm fields, oak woods, and crossing at least one branch of the Nippersink Creek. I find the vistas across farm fields along Thayer amazing. The view is fairly flat and most trees are in the distance, so they don't block the view. I'd like to explore some of the isolated woodlands out there sometime -- they seem so remote and mysterious!
In the middle part of the county, there is Collins Road running west from Woodstock across the flat, outwash plain that sits between the Woodstock and Marengo moraines. The road starts out straight and level, with beautiful views of an agricultural landscape. As Collins hits the Marengo Ridge glacial moraine, the character of the road is transformed into a hilly, wooded route - the vistas are gone, and trees are the norm.
Then there is Fleming Road, a 2 1/2 mile route that runs from Country Club Road at its south end northwest to Route 120 east of Woodstock. In that short stretch of road, one passes visible examples of the county's "swell and swale" glacial terrain, complete with kettles and hills that were left behind when the Wisconsin glacier retreated 12,000 years ago. Additionally, the road passes through perhaps the largest concentration of remnant oak woods in the county.
Scenic may be in the eyes of the beholder, but I'm sure glad for the scenery around McHenry County that I get to behold!