The best way to get around in the area is obviously by car. In the spring and summer, biking is also highly recommended. There are a lot of bike lanes and special bike roads with no cars.
If you love the American style of eating, you can try to enjoy the Frankie's Diner. There some finger-food and also burgers are served.
Starlight Coffee at Kirchstrase is nice for some hot java.
Outside of Bad Mergentheim you will find a nice village called Markelsheim with many nice restaurant with a pretty good drink voucher: Weinstube Schurk, Weinstube Lochner.
In Markelsheim at each corner and in each street you will find many wine bars. In summer in Markelsheim there are at every weekend any other parties, esp. wine parties. Don_Lt miss them!