I've taught myself how to range these drags, and it is actually very easy.
An anti-dragon shield is needed, and invent should be pretty much full of antifire pots. If you attack them, they will switch to fire attack, which will not be able to hurt you. Using a rune c'bow and broad bolts seemed to be very effective, allowing regular good hits, almost as good as melee.
The only problem is seeing the "Your resistance to dragonfire is about to run out!" message, as your screen gets completely spammed with the dragon's attacks.
