The common intersection on day 3 and day 4 is D55 / 51 just north of West Bend. If you go from Pocahontas to Algona skipping the left turn onto D55 toward Emmetsburg, it’s a 51 mile day. The route to Algona is part of the day 4 Ragbrai route, so it will be in better shape than off route options. Mileage from Algona to Mason City is about 71 also following the official RAGBRAI route.