Inlandsbanan route

Östersund to Gällivare is a long trip, even if it includes stops along the way. But you can of course make an overnight stop along the way if you want, that sort of depends on what you are interested in and what you want to see and do.

It's easy to get from Gällivare to Stockholm by direct overnight train, but if you want to make stops along the way consider Luleå or Umeå.

Thanks for the answer, Badger!
I haven't searched anything yet, but my idea is to enjoy the scenery and maybe do something fun if i can find it. Do you know if there's something interesting to do near Vilhelmina or Storuman? Those stops look like the best place to split the Östersund to Gällivare trip.
I will also look into Luleå and Umeå, thanks for the suggestion.

By the way, do you know if making more stops along the Inlandsbanan makes the trip more expensive or is it about the same price?
On the website I've only found prices of the packages tours or the 14-days card, not the single tickets. I've sent an e-mail to receive the notification about the release of the 2023 timetables though. Hopefully they will publish it in the next months or two.

There certainly is! They are not large cities by any means, but you can spend a night in one of them without feeling bored. If there is choice between the two I think my choice would be Vilhelmina but Storuman also has things to do.

Normally the northbound train makes a lunch stop just north of Vilhelmina, so you if you stop in Vilhelmina you need to make a choice if you alight in the town or continue a bit north and take a taxi back.

Thanks Badger! Your advice is always helpful.
If I decide to go, I will definitely report back. (Or ask a few more questions.)

Glad to hear that! Looking forward to the report!

If you decide on Vilhelmina, it has a well preserved old church town* that is worth a visit. Risfjälls sameslöjd is also a great place to visit for Sami art and handicraft, it's both a store and a small museum, https://en.sameslojd.se

*Church towns are collections of houses built around churches in northern Sweden so that people that lived far from the church had a place to sleep.

On return you could take the mainline train to Boden then the overnight sleeper to Stockholm

Or there is a through night sleeper train from Gallivare at 1957, arriving at Stockholm at 0926 next morning.
The day train departs at 0711, after changes at Boden (4 minutes), Umea (8 minutes) and Sundsvall it arrives at Stockholm at 1938.

Thanks everyone for the infos!