I don't think I actually found a route map, but there was a description of the starting point on the registration form, and I assumed that since it's 70 miles around the lake, that would be the route for the longer ride. It wasn't'
particularly hilly when I put that into mapmyride, just gentle 40-ft ups and downs. Flat is relative, and I tend to think of Florida-flat or Oklahoma/Texas-flat (where you can see for miles until the earth curves, and roads don't bend) as flat, and "normal-flat" as "flat-ish."
Camping will take a little more planning, but I think it would be fun. Either is fine, though. Thanks for offering your cabin and your brother's house, solveg!