You can pay a heck of a lot more for a hotel room in Claremont village and have the advantage of being right in the thick of things. Or you can stay here and have the advantages of paying significantly less, having a lovely, comfortable room, enjoying a relaxing walk into the village or to campus (Pomona's is the furthest, and it's about a 15 minute walk), and skipping over to Wolf's Market or TJ's for snacks or meal makings. By senior year the last place my kid wanted to go was the village - been there, done that! - so the Doubletree was even more appropriate as a base. In addition to Trader Joe's and Wolf's, there are grocery stores, coffee shops, drug stores, and anything else you need all nearby, as well as easy access to the highways - it couldn't be more convenient.
Keep in mind it's almost impossible to book for graduation: call ahead to find out when they begin taking reservations, and then be quick about it on the appointed day - they sold out in 10 minutes for graduation 2015. There simply aren't a lot of reasonable options in the area, and it's worth any effort you can make to score your room(s) there.