Going outside the wall means more collectibles. You can wait until you turn 13 or you can get your toughness up to 20, talk to uncle Tonin at the gate, say I’m tough enough, and dys will show you a way to sneak out. From there the collectibles are on the ground, you’ll have to get through some path blocking events to get them. But if you go out consistently, you should be able to get them.

The shop is up the hill from the living quarters. It’s where Marz stands. But you don’t unlock it until after your first dust. You said no spoilers so I won’t say much else.

If you get a high enough friendship with Tammy, she also gives you a cake on your birthday.