With my trip is exactly one month away I have 1 day of my itinerary designated to visit Hohenzollern Castle. We plan on driving from Heidelberg to Bisingen and having nothing else planned on our agenda for that day. My question(s) to those who have been there are: What is the best scenic route from Heidelberg to the castle? Also, can anyone recommend any other interesting sights around that area that we could possibly fill time with as well. I fear that we will tour the castle and then have nothing planned for the rest of the day and it would be a shame to drive back to Heidelberg and miss anything worth seeing close to Hohenzollern.
Towns along the Neckar such as Bad Wimpfen, Tuebingen. Schloss Lichtenstein, nearby caves
The most scenic route, by far, is to drive up the Neckar River from Heidelberg to Bad Wimfpen. This portion of the river looks similar to the more well-known Mittelrhein, with low mountains lining both sides of the river, castles and attractive towns. At a minimum, stop at Bad Wimpfen for a quick look around. The scenery from Heilbronn to Tübingen is less special, so you'll miss far less if you take the Autobahn routes.
If your main goal is to see Burg Hohenzollern, don't linger too long elsewhere. Yes, the drive from Heidelberg to there is not that far, especially by Autobahn, but neither is it insignificant either. Traffic can snarl to a halt around Stuttgart. A scenic drive up the Neckar river plus Burg Hohenzollern should fill most of a day.
On the Hohenzollern site, there are two, which one, depending on which side of the family? Burg Hohenzollern in Hechingen or Schloss Sigmaringen. If you are left with extra time en route to Heidelberg, when you reach Stuttgart veer off to the right to Marbach am Neckar to see the Schiller Nationalmuseum (of Goethe and Schiller fame) if you're interested in German literature)
I'm sure the OP wants to see Burg Hohenzollern, since they said "Bisingen". Actually, Bisingen is around the other side of the "mountain" from the entrance to Burg Hohenzollern. The road to the castle, K7110, intersects Hwy 27 just on the edge of Hechingen. On the most likely route, you'll go through Hechingen and get to the turnoff before you get to Bisingen. If the weather is good, you should see the castle as you come out of Hechingen; it really dominates the landscape.
Thank you all for the good advice! I will be posting my finalized itinerary soon so please take a look at that as well and critique and advise where you are able please!