I know this is a bit of a weird one, but i've been trying to find that theme because it just chills me out. I've tried finding it in the RPG Makers OST (not there) and i've been trying to find it through the games files, but theres so many, that i was hoping someone else here knew what it was before i go through every single one of them.

Update: Found it, and for anyone interested, it's Nyagical Mystery Tour in the bgm folder.