Not exactly sure these are what you're looking for. Both I use both of them. Keep in mind, neither are free.
1) iExit: Shows food and lodging along interstate and major highway exits. However, it also lists shopping malls (including outlet malls) and some roadside attractions.
2) RoadsideAmerica.com: Lists quirky and unusual attractions (think world's largest ball of twine). You can set it to look for attractions around you or at your destination. For example, within a few miles of me right now are the Florence Y'all Water Tower, the Ventriloquist Museum, a two-headed calf and one of the world's smallest churches. There are several different apps to correspond to different parts of the country. You have to pay for each one. I just have one, the app for Southeast USA, since I live in Kentucky.
HTH.
