Touring bike (cross bike with racks), tent and sleeping bag. (already got, so £0)
BA flight to Pisa on 1st May = £48, BA flight back from Rome (an extra day's ride to get there) = £73
Campsites, £10 per night (8 nights, £80 total).
Food £25 per day to eat well in OK restaurants (8 days, £200 total).
Map £5.
I reckon you could do the tour yourself for about £400 all in. And you wouldn't have to put up with a bunch of insufferable Rafa-types
.