The situation is pretty fluid. In Norway in 2001 we tended to use Internet Cafes. In Sweden these are tending to die out and we have mostly used Public Libraries. However you will probably have to book and some require you to take out usually free membership. Some marinas have free internet access but again this becomes pretty popular and it may be difficult to get on the computer. Some large cities do have I-cafes still. In the UK 3G seems from coverage maps to be pretty thin on the ground on the coast. As far as Iwas aware last year 3G was not readily available in Sweden.
GPRS is probably reasonably possible - it is supposed to work wherever you have a decent mobile signal and that is in most places in Sweden.
I have a nasty feeling that you need a 2 band mobile for Norway - at least you did in 2001. This may affect your ability to use either 3G or GPRS.
My Norwegian brother in law doesnt think of the tax people as well disposed just intermittently effective. The limits are indeed very tight and if you have more than the limit you do risk a large fine or you may be lucky. The customs man you meet may be very pleased to see you, he may have been cheated by an Englishman or he may just have a hangover. Its your choice whether to risk it, so long as you are aware of the situation.
I have to ay that Norway particularly the great fjords is fantastically beautiful. Sailing 50 miles inland in water 1.3 kilometres deep with hills the same distance above you and glaciers visible is very difficult to beat.
In our limited experience moorings for larger boats are more difficult to find when in the fjords. Most of the marinas are for small getabout workaday motorboats. You may be forced into commercial harbours. The weather can get so hot that you need to sail in the shadows of the cliffs. Alternatively it can rain for days and days.