Well, most of the hotels are off the IH20-Washington Road exit, which is no more than Google Maps would show you. That intersection is a bear at almost any hour of the day, and it's nothing but a desert of big-box cut-out businesses. Check out The Partridge Inn and the Queen Anne, both of which are closer to downtown, which is where you should spend you time in Augusta anyway.
Sites? Well.... The Laurel and Hardy Museum is in nearby Harlem, GA, right across from one of my favorite little coffee haunts, The Harlem Java House. Otherwise, enjoy the river walk area downtown, and check out the Morris Museum of Art; it's a great little regional museum that does a great job of showcasing local art and historical pieces. The canal trail off Riverside Drive is a wonderful way to experience the river, and if you like baseball, the GreenJackets team has a great park for games.
Restaurants. Well, I do have a few favorites. First, check out the Augsberg Haus restaurant, one of the best little German restaurants you'll find. Adolf and Hazel, the owners, love what they do and love where they are. The potato soup is out of this world. Thai Kitchen is by far the best thai food you'll get in the area. Yes; TK looks like (and is) a strip-mall restaurant next door to a supermarket. Go there anyway. Farmhaus burgers and the New Moon cafe downtown are fantastic fallbacks for daily meals: NM for breakfast, Farmhaus for lunch. Dinner gives you a ton of downtown options which are pricier but worth the money. Bee's Knees and Fuse are amazing; go if you can; and if you can get a table at Frog Hollow, it is perhaps Augusta's finest dining.
In Memphis visit the Peabody Hotel and watch the resident ducks march you dont have to stay there to see this, just check what time it happens, and also the Hard Rock Cafe. Nashville - Ryan Auditorium, Opryland Hotel,take a river tour on the General Jackson, walk downtown Music City at night.