Oslo is one of the best places, you have loads of gravel rides in the forests that surround it. And you also have plenty of rides along the fjords with some gravel options.

Røros is another great place for gravel rides with plenty of options but this is further north towards Trondheim.

Gol to is a great place with many gravel routes surrounding it (including Mjølkevegen and Rallarvegen is just a few stops on a train), but once again, this is in the middle of Norway.

Cycle Norway will be creating both Oslo and Røros gravel pages over this winter ready for next season.

I quickly made this page to show you some of the great routes around Oslo on gravel: http://www.cyclenorway.com/routes/oslo-gravel/

You will need to wait a few months for these pages to be completely ready. I will add two more months to your membership so you are assured of all this new info.