Is it important to model uneven terrain?
Just as with any scientific modeling, you should not take any shortcuts when building your model when you can avoid it. Oversimplifying your model can invalidate it. Certainly, those who will be scrutinizing your work will be looking for any inconsistencies and could question it. Probably the best way to avoid criticism is to validate your model by having close correlation between measured and calculated magnetic fields. If there are significant deviations, you will want to adjust the conductor heights to account for uneven terrain.
