It sounds like you want your cascading drop down menus to hook up to data offline.
Hard code it with a static Table()--sounds like this is what you're already doing.
Connect a static table from Excel: View > Data sources > Import from Excel
Collect the options you want locally.
If your options do not change or change often, the best option is the second.
If the cascading dropdowns would change, then you'll want the third option. Here's an example:
// Load any cached data. Suppress any errors.
LoadData(localcollection1, "localcollection1", false);
LoadData(localcollection2, "localcollection2", false);
// If there was not data cached, attempt to do it now.
// Collect the items from a SharePoint list.
// Save the table to the local storage.
// Repeat the same for other tables.
Now that the data is local, you can make localcollection2 dependent on localcollection1 in the Items property of Dropdown2: