A National Parks pass for a year
Her first passport (and a holder)
Take her to get a new driver’s license with a gold star on it
I don’t know her financial situation but it may have cost her a lot to get the citizenship and she may not have the funds to get all these things done immediately.
I just learned that a college friend only became a citizen about 20 years ago (I’ve known her for 50 years). I knew her mother is Dutch, but I had always assumed she’d been born in the US after her mother moved here. Nope.