Working on the assumption the Front Office is also a web application designed for the iPad you need to look at a HTML5 features supported by Safari within iOS called Cache Manifest and WebSQL.
Cache manifest will instruct the iPad to download all the website components required to operate in an offline capacity. Once it's finished loading for the first time you can put the device in aeroplane mode and the website will still works.
You can the use WebSQL as local storage. This is an in browser implementation of SQL Lite which can be used to store information within the client for recall at a later date.
HTML5 - Web SQL Database
A beginner's guide to using the application cache