I agree it was a long day. We did this tour the day before we left Europe this past June.
Tour included: Kronborg, Viking Museum, Roskilde, and Fredricksborg.
1) Roskilde: Many kings are buried here, that's part of why it's a Unesco site. The other reason, well there are lots of architectural styles present. Amazing doors. Crypts (not catacombs that I am aware of, but ??) there were many, and all were unique. Many were very ornate. Something like 30+ lil nooks (not the technical term, sue me).
2)Viking museum, I wrote a whole review for this. But, highly enjoyable. Four- five ruins found in a nearby fjord. The video which describes how the preservation of the ships occurred was very interesting. Dig the outdoor spaces, plan in advance and you can take a boat trip on a viking ship (re-creation).
3) Fredricksborg: Oh la la, fancy castle. Pleasure palace according to our guide, wish I remembered his name, he was Norwegian that's all I recall. The chapel with all the coats of arms, don't miss it. Just amazing detail all around. The gardens looked great too, if you have time.
4) Kronborg: Hamlet castle, heck yeah. Lil shakespeare and dancing demo, oh it was lovely. A more "plain" everyday castle, if there is such a thing. The prison/ underneath the castle, uneven walking, dark, spooky, damp. Cannons, they work! Too cool. You can see over to Sweden, so that's cool. Two moats, high security here. read more