When exiting Cedar Rapids, there are 3 significant climbs and none of them are particularly difficult. The only problem will be with the first real climb on 15th Ave from Otis road to McCarthy Road. The problem is the road is narrow and is a potential choke point if it is crowded with riders struggling to get up the hill. A better route would have riders stay on 12th Ave and follow it till it meets up with McCarthy Road with about only a few extra feet of climb. McCarthy Road will also have some riders struggle but I train on these hills so they are not impossible, just narrow at places.
Some riders will just bypass these hills and enjoy a peaceful ride on Otis Road to Bertram Road to Mt.Vernon Road. But there are no services going that way, whereas there are convenience stores and a Hy Vee if the route is followed. Your mileage may vary. Enjoy.