We will be in Denmark and Sweden

We will definetly stop at Ribe Viking site as we want to see the town, it's on our route

Also definitely Vasa in Sweden

So what are the other best sites?

Foteviken? Birka?

The Viking Ship Museum in Roskilde.
http://www.vikingeskibsmuseet.dk/en/

Enjoy!

Should we go there if going to Ribe and Vasa? How are they different?

I haven't been to Ribe.

As I understand it, Vasa was not a Viking ship. Vasa is stunning and well worthing seeing, IMO, but it was built in the 1600s, long after the Viking era, as least I understand it. The ships in the museum in Roskilde are actual Viking era ships, built about 1,000 years ago.

And you might also want to visit Gamla Uppsala....

The Vasa has nothing to do with the Vikings, although it is certainly worth seeing. The museum has done a very good job.

Where are you doing your research?

We loved the Viking site outside Ribe, and also Gamla Uppsala

And although not Viking, Vasa was absolutely awesome!

Thanks for reporting back!

Trelleborg is pretty impressive
http://natmus.dk/museerne/trelleborg/