I really want to revamp DS's playroom because it's not painted nor does it have any type of kid things on the wall. I really have no idea what to do with it because it's directly connected to my living room only separated by a large archway so I don't want to go all crazy with it like I probably would if it were in another section of the house. Any ideas?

What I have in it for possible matching references:
PnP - colors are brown & rainbow
Amazon.com: Fisher-Price Luv You Zoo 3-in-1 Playard: Baby

Amazon.com: Graco SimpleSwitch Highchair and Booster, Zooland: Baby

Colorful alphabet foam mat

Cars toy/book organizer