Bathinda makes a useful base for southern Punjab. The two essential excursions are the great Sikh seat at Damdama Sahib and the goddess temple at Maiser Khana; with more time you can push out to the cotton-growing villages along the Rajasthan border.
If you have a car for the day, combining Damdama Sahib in the morning with lunch in the village of Talwandi Sabo and a quick stop at Maiser Khana on the way back makes for a satisfying loop.