I think the basic assumption with a Spirit (at least in this setting) is that it occupies a Nevernever Demesne of its own making, which will colocate with a location that is important to said spirit (and possibly with other, thematically similar locations).
While in its Demesne, it presumably has full sensory powers. When in the real world, it blunders about on instinct, causing whatever mayhem it is driven to cause - almost as if sleepwalking - which I presume would require a minimal amount of sensory data. But when actually confronted with resistance and forced to respond, I *think* that is when it has to manifest.
Edit: but I don't have the rulebooks in front of me.