I made the mistake of attempting this quest at stage 4 vampirism, not really knowing beforehand what I was getting myself into. I struggled my way through the first frozen section by mist forming from torch to torch, having to wait a minute or so at each one to regen if I strayed too far at any point. Then made it through the draugr dungeon (where there weren't any NPCs I could feed on, of course) to finally reach the Dragon Priest at which point I found I couldn't gather the kindling or light campfires because they were bugged. I tried to fight him from the one torch nearby that was already lit, but you can imagine how well that went, fighting a V5 Dragon Priest and the frost at the same time with my squishy stage 4 NB.
I mean... does the frost effect have to be SO deadly? It took me from full to zero health in all of 10 seconds, forgetting the V5 boss I was forced to solo since veteran zones are all but abandoned.