Getting around the various lands of Alton Towers couldn't be easier than by using the sky trams. The overhead trams are also great fun to go in, and there's always something to see. They run very regularly, and stop at each of the main areas of the park. Might not be the best idea if you're afraid of heights!
Best is if you have your own car (although you pay £3 for the parking and £10 if you want the best location!). It is well signposted from the hub of motorways around Stoke-on-Trent.
Don't despair if you haven't got a car. Virgin, Central and Midland Mainline trains all have package deals including bus transfer from London and other cities.