> recently purchased a d7000. > > My wife and I will be taking a European river cruise in May. > Nikon 18-105mm f/3.5-5.6 AF-S DX
> I’m thinking I should have purchased just the > body and bought a more versatile lens.
Why? What do you mean by "versatile"?
Your 18-105 is an AMAZING lens! Absent some specific and fairly specialized requirements, its all you will ever need.
What sort of photographs do you want to take? What sort of photographs do you want to bring back from your trip?
FWIW, my advice to you is to spend the next few months learning everything you can about digital photography, post-processing, RAW format, workflow, etc. You already have all the gear you need. Your greatest return on investment (both in terms of time and money) will come from improving your knowledge base. If you can find some classes to take, go for it.
And take lots and lots of photographs. You'll learn more from an hour of real-world practice than you will in a month of reading opinions online.