To reach any city in Lapland, the connectivity is via Helsinki. So if your are travelling from non-EU countries, its better to find connectivity till Helsinki. Stay over for a night in Helsinki and take the first early morning flight to the cities in Lapland
1. If you want to start your trip from Rovaniemi, than they have flight early morning which reaches around 9 am, so one can have full day to explore.
2. If You want to start your trip from Saariselkä, Then you have to reach Ivalo first and take the bus to Saariselkä which is just 20-30 mins from Ivalo.
So for Ivalo either try above option or look for end to end ticket as per the preference.
Visit the page Amazing Things to do in Lapland