We flew into Ivalo some 15 years ago early April (Easter was late that year) so my information is very dated, but then I don't think that much changes above the Arctic Circle. We didn't stay in Ivalo, taking the coach to the Suomen Latu Kiilopää Fell Centre near Saariselkä.
Google Maps "Quick facts": Saariselkä is a resort village in northern Finland. It's a gateway to the trails and ski areas of mountainous Urho Kekkonen National Park. The village's Destination Northernmost Europe exhibition has a panorama theater with films on the region’s plant and animal life, including reindeer. To the north, the lakefront Sámi Cultural Center Sajos includes a craft shop and a library devoted to the indigenous Sami people.
The Kiilopää Fell Centre boarders the Urho Kekkonen NP noted above. We encountered a reindeer herd skiing in the National Park.
We're skiers but I understand that resort areas offer snowmobile, dog sled and even reindeer sled adventures.