One of your first stops should be Claypipe Visitors Centre. Here, you'll be able to orient yourself and get some great tips before you begin exploring.
You'll soon find out why this Knockcroghery tourist information center is popular with travelers. If you're looking for more to do and see here, Dr. Hyde Park, Sacred Heart Church, and Roscommon Castle are in this area too. They won't take you long to reach from Claypipe Visitors Centre.