Reign of Winter advice. Spoilers requested.

[Ectar]

I know it's a number of years old, but I still can't find the specific advice I'm looking for.
Most people recommend full casters, characters that can deal reliable fire damage, gunslingers, and druids above most other classes for this AP.
Full casters are obviously always powerful, fire damage is strong v.s. all the cold-themed foes, and I've read the 5th book, so I know why gunslingers are appropriate.
Druids has me baffled, though. Someone posted their recommendation as druids and gunslingers, but wouldn't say why because of spoilers.

As incipient GM of a RoW campaign, I'd like to know why druids are specifically recommended. Give me all the spoilers, 'cause I'm gonna read the books anyway. I just want to know the basis for providing advice to the players before character creation.

By the by, I will be giving them copies of the player's guide to peruse; I still want to know the reasoning.

[Val'bryn2]

Have only read parts of it, but I think it's due mostly to when you are teleported from Taldor, midsummer, to Irrisen, so someone with nature skills would be instrumental in keeping the party alive, finding food and warmth, etc.

[TriOmegaZero]

There are a lot of overland/wilderness encounters. A druid is a strong contender in those areas thanks to effective spells in those locations and the ability to handle large numbers of animal/fey opponents.

[voideternal]

Book 3's megadungeon is not big-creature friendly for combat-focused wild-shaping druids.
Edit - Also, Fey are one of the most common enemies in this AP, so Resist Nature's Lure applies quite often.

[Cavall]

Between Fey, dealing with cold effects and cold monsters, having someone with nature spells and fire damage is pretty simple logic.

I would not reccomend gunslinger at the start. In fact all ranged characters will suffer a massive difficulty spike due to a storm raging and cutting ranges in half and adding 4 to the dc of targets. That means without precise shot, most shots are at +12 with soft cover and in combat. Even with touch AC that's not likely to hit.

Once you get out of the storm, (pretty much book one) you'll be ok.

[Ectar]

Alrighty.

I was thinking there was a specific piece of equipment, perhaps an NPC interaction, or something that specifically incentivizes druids over other classes.
If it's just the general "Druids are good v.s. fey, less affected by weather, can do fire damage, and survivalism" that's fine. I was just under the impression that it was more specific than that.