The museum provides highly interactive storytelling, which would be great for children, and some fascinating stories about the power struggles and human sacrifices of 18th Century Rajasthan. There can be a lack of English explanation, though, so take a hotel guide with you to translate.
There are also camel rides available outside the fort, and a selection of its famous rose water. The region is now known for the growing of roses, and even supplies RAAS Devigarh with the flowers.
Haldighati is close to Nathdwara, so could be covered as the first stop in a morning excursion.