This. I have used simple HTML5 web applications with the meta tags to allow running in 'app mode' (no browser chrome etc) and then enabling guided access mode on iPads (mounted in display stands, mostly) many times, and find it works suitably well to lock the device to a single purpose. You need to consider a few edge-cases (for example not allowing text selection and long-press, which allows the user to access the 'look up' function, and making sure there are no links to any external URLs etc, but once you've covered off those things, it works as a fairly effective way to provide a 'kiosk' style interface.