Originally Posted by
beofotch
Now that I research it a bit (train to city and then pick up from Oslo the next morning would be ideal) - there are no locations open on Sunday before Noon - and we want to get an early start to enjoy the drive - say 8AM. So we might be stuck picking up Saturday night at the airport or downtown and pay for parking (unless we potentially park the car, while still under our possession, on Avis property for "free" parking). I used to this in Geneva when I lived next door to an Avis.
No Avis propertys to use for "free" as I know their facilities in the city center or at the airport.
Hertz in city center at Radisson Blu Scandinavia Hotel opens at 9.00 am at Sundays.
My recommmendation would be to pick up rental car at the airport and drive to city center. If free parking is important, stay at a hotel just outside the very narrow center between the castle, Aker Brygge and main railway station and you probably find a free street parking with in a few hundred meters. For example Scandic KNA, Rica Hotel Bygdøy Allé or other hotel in the Frogner area.
Have a nice drive across the "Hardangervidda" to Bergen!