> It's a long way to Sweden, even further to Finland.
It's a long way to anywhere from Scotland but I love driving. My trip to Slovenia, with stops in Germany and NL to visit friends was over 3,000 miles this year. The trip I'm planning to Sweden and Finland may well end up more than 5,000.
I don't use the tunnel, I used to take the Harwich-Hoek ferry to get a nights sleep in while travelling, but now I prefer the dog friendly cabins on the Hull-Rotterdam route, saves the busy part of England for me and also means you arrive fresh the next morning and can tick off a lot of miles before stopping again. Motorway driving on the continent is much easier than here, people merge and use lanes better don't you find?
> We're just planning to do the drive to Stockholm, will probably have to be in mid December
I'm guessing you'll need winter tyres fitted then?
I like to travel in April or May, not too cold, not too hot

I'm thinking the bridge from Denmark then up the West coast to Gothenburg, then cut across to just above Stockholm and drive up the east coast, it looks prettier? I'll cross into Finland at the top of the Gulf, not going as far as Norway. I'm not sure what to do then, maybe the ferry from Turku to Stockholm? Have you ever done that?