lucky you it will be gorgeous in may..personally i would base myself in sorrento and take trips out and about from there.make sure you get an hotel in sorrento town itself a lot of hotels are on the outskirts or in the next town.we stayed at the tramantano 4* very regal but very friendly and in an ideal position right up on the cliff...fantastic views of the bay of naples and vesuvious.the amalfi drive is a wonderful journey probably one of the best in the world we did it on a public bus only cost 6 euro(2007) the coaches arent allowed to follow the coast road both ways..a private taxi would be better but you would be much lower and have to stop many times for views.you can catch the train to get to all the other attractions pompeii,herculean etc etc...also you can get combined train admission tickets to the attractions.a trip via boat to capri is a must wonderful walks and the strangest place in the world to find designer shops..lots and lots to do in sorrento and the worlds best ice cream!hope this of some help
tony