One thing we did for which I am gratefull is to take a ferry to Helsinki. I would have loved to stay in Finland for longer. Copenhagen was far more expensive than Stockholm. A Best Western was 300 bucks a night. Amsterdam was the cheapest place we visited. Meals were reasonable and you could find some tremendous bargains as far as lodging goes. And as much as people like to deride Amsterdam, it felt safe even at 2:00 AM. The Ann Frank House is a must see.
Last time I was there it cost $100 to fill up the rental Volvo. (20 gal at $US5)