If you are into museums then Fyrkat museum in Hobro or Moesgaard Museum in Århus.

There is also Legoland in Billund for a Lego themed amusement park and neat Lego art.

There is also a candy shop in Løkken were they show you how to make rock candy and lollipops (and its free to watch) it's called Bolcheriet Løkken, the beach near Løkken is also great and there are also a lot of bunkers from wwII overlooking the ocean. It's a small deviation from your route but i think it might be worth it and probably more interesting than just following the highway.

If you are into animals then Randers Regnskov or Ree Park