The importance of this town lies in the fact that this was the starting point of the fight for Mexican independence from the Spanish empire in 1810, led by priest Miguel Hidalgo y Costilla. The quiet atmosphere in this town makes it really charming and the absence of tourist crowds could make it a highlight in your trip.
To reach Dolores Hidalgo you should be able to get a bus from Guanajuato, San Miguel de Allende or Leon all of them are around 1 hour away. Taking a bus from Queretaro is also an option. From Mexico City you need to take a bus to any of the before mentioned cities and then to Dolores. The bus station is located at Hidalgo Street and Rio Dolores.
The town is really small, everything is within walking distance.
Every night there's a re-creation of the famous cry for freedom at the main square with light and sound effects.
Dolores is famous for its Talavera Ceramic (pottery) items such as tiles, vases, pots, etc. Experts say is one of the best places to buy this kind of goods. Next to the parish, there are several stalls selling small cacti, local liquors such as honey liquor or cacti liquor, and other local crafts. Buying from them will make their day.
Dolores is famous for its exotic ice cream flavors. Try them at the Main Square, there are two vendors, offering strange flavors such as Mole (chili and chocolate sauce), Beer, Strawberries and Cream, Avocado, etc. Each ice cream or "Nieve" in Spanish is around $15 pesos.
In Dolores there are clubs and bars that you can go to just ask taxi cab drivers and they would take you anywhere. The most famous are Gruperoona and Ceasars
Dolores is a safe place by Mexican standards. Overall, people are nice and willing to help if you need directions.