Reserve a place on Best Park Arctic.
Artic Circle / Rovaniemi – BestPark
There you can use electricity, use sauna, shower, wash clothes if you need.

Visit Santa Park. There is reindeer and husky safari and a lot to look at for one day.

Drive 20 km north from Rovaniemi and spend one evening and maybe one night on VIKAKÖNGÄS FIREPLACE.
https://maps.app.goo.gl/SLJ55cQBwqoJXwQd7
They have free wood that you can use and 2-3 fireplaces.
If clear sky, you have good chance to see Northern Lights.
Buy sausage and tasty drinks from a shop before and enjoy.
I recommend to buy WILHELM-sausage or some other A-Class sausage.
Not anything with text ”RUOKAMAKKARA”.
There is big parking areas at Vikaköngäs, so you can even stay there all night and sleep in the van.

If you still have time, how about visiting a sauna and try ice water swimming.
KESÄTEKEMISEN KESKUS ROISKE