Assuming he has someone he knows around to sort of buffer the whole experience, he’d be enchanted! Everything is so bright and vibrant and open out there, and the air moves so much more than in the stuffy walls of the motel. It wouldn’t even smell the same, with all the scents of flowers, trees, mud, and the like.
He doesn’t see many live plants at all normally. Chances are Oscar would be amazed even by a leaf or a blade of grass, gently feeling the texture or watching them move in the breeze. It’d be a charming experience for him, for sure.