And to the exhausted randonneur, many brevet routes seem to have been concocted by sadistic devils, with 18% climbs late in the route. So yeah, include more hills in your long rides, but ride them easy for the first 2-3 months. Try to ride them at a level that doesn't hurt. After your conditioning is good, start riding the later ones at a level that does hurt. Try for at least 50' of climbing per mile, averaged over the route.