Have fun! Holland is awesome. I can understand that it's tough to go into a situation like this without any pretense and in my experience that is really what makes things nerve wracking. I probably don't have to tell you that the only thing you need, to have a good time, is a positive outlook.
I can say though, that I'm excited for you; it just sounds so romantic. I had known my boyfriend for several years before we started going out, so I felt very safe taking it to the next level. I can only imagine the sense of adventure you must be feeling. You have to come back with stories so I can live vicariously through you (not that I have any regrets, we have had tons of our own delightful adventures).
My boyfriend and I spent two weeks backpacking through Europe without nearly enough money to live modestly, let alone comfortably. The experience was enough to test the strongest of relationships, but we ended up have the most amazing time of our lives. We ended up rooming with people that we had only just met, that asked for nothing in exchange. We saw things that I think one might have missed if you spent thousands on guided tours. There were stressful moments but neither of us had any expectation of what the experience would be like, which is what I think made it so magical. I can honestly say that we had never (and rarely since) made love the way we did almost every night of those two weeks. I think that it had a lot to do with the anticipation of feeling something so familiar in contrast to the completely alien experience of being at the will of fate. There were tough moments (getting separated in Paris, without any way of communicating with each other) but it only made the experience that much more potent.
This experience may not parallel what you have to look forward to but I hope that you can take away a similar feeling no matter what the outcome.
Brit