A nice WIP.
Player sprite is adorable, especially with the hat animation.
Collisions still need some work

But your main problem is that you're already out of map room.
This can be addressed by using compression PX9? (https://www.lexaloffle.com/bbs/?tid=34058 )
and/or alternate map system. Picomap ? ( https://www.lexaloffle.com/bbs/?tid=42848 )
and/or multiple chained carts.