It depends on how confident you are with your new wheelset. Was it made by your LBS? Was it home brewed? I've ridden centuries on wheelsets I've built with less than a hundred miles on them. If they've been built, stress-relieved, trued and set up correctly, then they're usually good for several thousands of miles without much attention, barring accidents, potholes etc.
So, are you feeling lucky, punk?
- Wil
PS: Good luck with the ride!
PPS: Other thoughts - I bought a set of wheels for my MTB from eBay, and was surprised to find that the tension was about half of what I would have expected it to be. The wheels had been put together, and trued, and stress-relieved, but had not been brought up to tension. I'm sure they would have worked OK, even for a century, but I'm certain that spoke breakage would have happened sooner rather than later (or never). So, do you already have the wheels, or are you still waiting for them? You might want to check their tension.