If you wanted further afield, you could get the train all the way to Oslo!
5-7 hours, but it's apparently the highest altitude by a mainline train achieved in continental Europe! Certainly spectacular I'll give it that, My missus complained about how many photos I took thru the window, and the same train hooks up with the Flam railway.
Mr's and I had 1st class (komfort - inc. complimentary drinks larger seats) day train and 2nd class (still pretty classy) overnight sleeper back. as a 24-36 hour trip between the two cities. Was a bargain. The entire return train journey was less than London-Scotland standard single fare!! Ignoring a sleeper cabin a seated fare can start from as little as £30ish each way
Norwegian Railways website
Car hire can be expensive and the country is mostly ruled by a national speed limit of 80km/h give or take some Motorways nearer Oslo.
2 Erdinger wheat beers cost us over £30 in Bergen last year but I new that (My mum is Norwegian expat of 45 years I go regularly to Oslo to visit her family)
Try not to eat english, if you don't mind living off 'northern european style hard/crisp breads and lots of cheese and cured meats, fish, potato (basically anything you could by in IKEA food dept in can be fairly OK) The country basically has something like a 100% luxury tax on things like fizzy pop, booze, sweets etc, so avoid them and stick to staple things.