You can use Set Skeletal Mesh for your character component, and use an Overlap system with trigger volumes to change the character.
In your character BP, make a custom event (or function; doesn’t really matter I suppose) that fires into a Set Skeletal Mesh. You could have an event called To Indoor Character and an event called To Outdoor Character. If you have any other components that would to change besides the skeletal mesh, you’ll need to set those too.
You can click the volume in the level and right click in the level BP to get the OnActorBeginOverlap node. Take the actor output from that and plug it into a Cast to your character class node. Take the output from there and call one of your events.
PS If you need pics I can do that. I just can’t as I’m writing this right now.