When my whole family went to Disney in 2006, we found that staying on Disney property would be cheaper overall. They have about 25 hotels on their property, from cheap and simple (yet still cute and themed) to luxurious. There are plenty of package deals to chose from, and if you stay on their property, you can get packages with vouchers for meals (which is a WHOLE lot cheaper than just buying food in the parks), and discounts on park tickets and other attractions. Plus you can use their transportation buses, trams, ferryboats, etc.
Tell her to pick up the most recent copy of Birnbaum's Disney Guide. It is a wealth of information.