where to go on my trip?

So now that we have our trip planed I’m trying to come up with the best way to get home after my friends leave. I have going up north and doing Denmark, Norway, Sweden, Finland. Or doing France, Spain, Portugal. I’m getting home through Iceland with stops in London, Scotland and hopefully time to go back over to Iceland. But the middle part I don’t know what to do. I have been to 2 of each of the countries with both plans, but only some of it. So now off to plan….

Any Suggestions out there???