You don't need broadband on mac to sync with iPad
The new ios5 on iPads allows for a plot more stuff to be done over the 3G connection, but you may still want broadband o download music, updates etc, just to save on 3G.
If you have broad band then the iCloud becomes more useful. As in download a tune on way to work it will be on your pc when you get home so already synced.
If you can get the iPad from apple shop. They will set it all up for you and quell any fears you may have.
Pluging your iPad I. To computer and syncing does not require any form of broadband