How should I train for a hilly ride while living in a flat country? I'm kicking around the idea of riding the Curadmír in the spring of 2015 (almost 600km over 3 days across Northern Ireland), a ride that would obviously have a lot of elevation changes in it (~2000m/day). A year is a lot of time to prepare for it, except for one small problem.

I live in the Netherlands. 



A country almost entirely flat and almost entirely below sea level. The biggest hill within 250km of my home is a highway overpass.

Short of getting on a train to the Kapelmuur every other weekend from October to May, how would you recommend I train for riding hills without, you know, riding hills?
Intervals. Lots of intervals. I had a similar problem when training for the Seattle-To-Vancouver ride while living in southern Michigan. We have hills up north and I took a few trips there before the ride, but it really wasn't enough to reduce the suck. This year, I've taken to doing tons of intervals with a regimented training program. In order to keep myself honest, I've been using my bike in a trainer with trainerroad. The measurable progress is rewarding and knowing when I am slacking off is incredibly motivating.