TBH, the driving is probably a good idea, theres loads of riding going up the coast of Sweden, not massive altitude, but lots of really nice trails.
Hallandsås, nice trail centre, fairly compact, probably a long days drive from Hook of Holland.
Göteborg trails, maybe 7-800km of riding in total. Centred on the city. Think there was a video on here a few months ago. Thats about 90 mins north of Hallandsås.
Then you’ve got the stuff round Uddevalla, which is my “local” area. Probably a three hundred km of trails from swoopy singletrack to nasty rocky drops and steps (up and down) unfortunately a lot of it isn’t marked or mapped yet (and may never be). Another hour north of GBG.
Then you are only 90 mins from the Norwegian border, and there are a few places with a few bits and pieces that might be worth exploring (foot or bike).