Druid Cantrips for Storm King's Thunder (SKT)

[Merudo]

I'll be playing as a Goblin Druid for SKT, starting at level 5.

I am going to take Guidance for sure. I'm not sure what other 2 cantrips to take, though.

Primal Savagery seems solid, especially with my Goblin ability to attack then disengage as a bonus action. However I hear having a long range attack is important in SKT.

Thorn Whip is fun but with so many giants in the adventure, I'm not sure I'll be able to pull much.
Frostbite relies on CON save, which the Giants are amazing at.

I guess this leaves me with nothing but Produce Flame as the third cantrip?

[HiveStriker]

Hi!

You made a pretty good analysis. I'd still pick Thorns Whip though, because even if you cannot use it against Giants, it can still be usable against many other targets. More importantly, it has the same range as Produce Flame but suffers no disadvantage in melee range. I mean, you should try and steer away from melee in the first place, but you won't always have a choice. ^^

If you'd like a "real" ranged option, I'm afraid your only viable choice without feat/multiclass is Magic Stone. It's usually overlooked by people, because it's supposedly best used with a sling, meaning DEX people who will arguably prefer a short bow in the first place.
It does allow you to make a ranged attack up to 60 feet though, which is much more reasonable if you want to stay in backline (and it may be allowed to benefit from Spell Sniper technically - not saying it's a worth choice for you though ^^).
And if you have a Rogue in party, it may be situationally helpful for him until/unless he gets another way to make its attacks magical.
Not sure how better than Frostbite it is in practice though, no idea of Giant's AC. Also, obviously Magic Stone is much worse in action economy since it won't scale with level like all other cantrips do (which is, incidentally, a missed occasion imo).

I still like Produce Flame for the utility aspect though (ensuring campfire, providing light) but it may be useless to your party, and it sadly has same range as Thorns Whip.

So, honestly, I'd say "stick with just Thorns Whip and whatever last cantrip, pick aiming for utility first (even if you end with a non-attack cantrip)".
If you really want a better cantrip that badly, I'm afraid you'll have no other choice than picking Magic Initiate: Cleric or (better imo unless you have a decent chance of reaching level 20) dipping one level into Life (amazing Healing Spirit) or Grave (amazing Spare The Dying)...
To get Sacred Flame (DEX save, radiant, ignores cover, 60 feet, the ultimate best you can ever get from WIS-based cantrips) or Toll The Dead (necrotic damage BUT WIS save which is even better, so close contender for the title).