Haparanda to Denmark road trip

Hej Sverige, Finland checking in here! I'm planning a little road trip through your country on my way to go visit some family in Belgium and I'm looking for nice places to stop at. I'll enter Sweden in Haparanda and will cross to Denmark either in Malmö, Helsingborg or Gothenburg. I plan to follow the coast until around Gävle and then go inland, but I'm open to small diversions to see nice places.

I will probably use your allemansrätten, so any good camping spots are also appreciated!