I got a big problem. I just find out my flight land 23:00 at Sandefjord Airport and it is far away to Oslo City Centre. As I will be travelling with family so should I book a mini bus in advance? How long it will take? How much will it charge? Actually, my airbnb house is located not at Oslo, so if I take train/tram to Oslo city centre, is it easy to get a taxi in the train station after midnight?
I made the mistake of flying in to TRF a number of years ago. (TRF is considered an Oslo airport). I arrived late afternoon and it took two bus rides and more than two hours to get to Oslo.
If your flight arrives at 23:00 your better alternative may be to book lodging at a hotel near the TRF airfield for the night and head into Oslo the next morning.
Train options: https://www.nsb.no/en/our-destinations/oslo-torp
Check the R11 train schedule: https://www.nsb.no/en/timetables/timetables/_attachment/13985?_ts=15c5e103b08
The Torp-ekspressen airport bus operates between Oslo Bus Terminal and Sandefjord Airport Torp. The travel time is approx. 1 hour and 45 minutes.
If you do get to Oslo at night (early morning) taxis are common around bar closing time because Norwegians do not drink then drive.