The Norway road trip .........
Definitely worth doing .......
Main thing you need to know is .......... speed limits

.....
They do not mess about, if it says 70, you drive 65 and so on ........
Minor infractions, ie 68 in a 60 will get you a 300 pound fine, and it escalates quickly.
...... and being in the middle of nowhere on top of a mountain means nothing

they are always where you least expect them.
The only real motorways are around Oslo ...... so any trip will take time.
From Oslo you can head west towards Stavanger then take the E39 coast road all the way North, great trip but involves lots of ferries, average cost is 20 quid a crossing - can mount up really quickly.
An alternative is Oslo to Elverum, then the mountain road to Trondheim ...... awesome drive, but watch your speed, not just speed traps but quite often the odd moose lolol.
A good trip is Oslo / Elverum / Trondheim / then east to Sweden via Are ..... if its winter pretty much guaranteed snow.
Lots of toll roads - some register your plate, some are manual ........ a rental car will have a transponder in it so tolls will be charged to your credit card - in a private car its a lot cheaper to register your car/credit card at http://www.autopass.no/en/visitors-payment fee's can be up to 50% cheaper that way.
Allow up to 300 quid for tolls / ferries on the average holiday.
Don't bother with Oslo - its completely over run with errrrrrrr imported undesirables who have one goal, robbing you

, its only Oslo though, everywhere is else is pretty cool.
In winter all rentals are fitted with proper Scandic Winter tyres ..... no worries there.
well worth the time.......