The only problem is you can't log on to the WIFI without having the right credentials.

At the end of February, is this bar study? Flying to another island isn't going to do you any good--the only thing you'll find out there are coffee shops, book stores, and the public libraries (Wifi will likely be an issue here as well), which are all things you can find on Oahu. Personally, I'd just request a quiet hotel room with comp WIFI outside Waikiki, e.g., the Ihilani. Unless you still want some nightlife when taking a break from studying. Or check VRBO.