Do caster out of combat options matter?

[clash]

What if the DM doesn't have a plot planned out?
What if the DM is reactive to what the players do, instead of having a set path in mind?

Then speaking as a DM it would be the same amount of work either way but would likely provide me more time to prepare for the planar adventure in the case where they are looking for a portal first. If the players want to get to the plane of fire in but going to say yes you can plane shift there but no one else in the world can help you get there if you don't know the spell.

I fail to see how getting there without the spell is requiring me to be more permissive