I'll just jump in here with a few tidbits about this from my perspective.
Steve and I never did much travelling before we had kids. We wish now that we had. We love experiencing new cities together. We discovered that when we travel with our kids it's a totally different type of experience than when we travel alone.
When we're with the kids, we have to make sure they are happy, entertained, and comfortable. So when we DO take them travelling with us we plan our activities around things the kids will enjoy.
When we're not with the kids, we like to go to seminars (not kid-friendly), and meditate for an hour on a rock (kids won't let us do that either), and spend a long time gazing at art in museums or playing in the science museum.
So there are two types of trips we like to take. The kind where we are focused on the kids and their needs, likes, and dislikes, and the kind where we can be romantic, take our time, be alone, reconnect with eachother, etc.
We don't have family who could travel with us for that long, and we don't want to leave them behind for that long either. So basically we're waiting until they are older before we take them on long vacations with us.
We'll get to it eventually. We're patient.
I like the idea of bringing along a nanny, though, so we can spend some time doing fun kid things with the kids, and then maybe do some more adult fun things in the evenings. That certainly seems like the most viable option in the future.
Thanks for your ideas. I would love to see Machu Pichu