Regarding gas, it is priced in guilders & litres so you have to do the conversion. The price on the pump is roughly double what you will pay in USD. There may be some self service but there is usually an attendant to pump the gas and I do not know of any price difference. 18.40 NAF is roughly $10USD.

USD are accepted everywhere and without much exchange problem on the Dutch side. On the French side they often set their own exchange rate with the euro and it is not always the going or current published rate.

When departing you will go through 2-3 security checks but you clear C/I at your first port of US entry.