There are frequent train services connecting Hanover and Hildesheim which is only about 30 minutes or alternatively you can drive and take the A7. ICE trains also connect Hildesheim to Gottingen and Braunschweig.
I found the best way to see the sights of Hildesheim was by walking but I believe you can catch the bus into town from the Hauptbahnhof (e.g. Bus number 1) instead of making the 750m walk.
The best way is to go by car. Just take the A7 from
Hamburg or Kassel, straight to Hildesheim.
Just take a walk. Thru all the shops in the main
shopping area downtown. It´s all close together and it´s fun on saturday,because there are all these people making music and stuff.