This is not about transport in Praia da Rocha but it is about eating out believe me you should try The Jackaranda Resturant in Praia do Vau. It has the best quality food at very reasonable prices. It is own and run by Robin and Hunny. So give it a try you will not be sorry.
The roads have improved no end since the late eighties, faro to the resort is 30 mins in a taxi for 50 euros, hire a car its cheaper! you can get a bus for 12 euros each way details to follow!
we drove from seville this year as the price was so cheap its about 160 miles but the roads are toll free and empty did it in just over two hours and didnt get burned by the airlines for flying into the algarve.
there is a tourist train that takes you about the resort and a small bus that circulates the resort for about a euro. You can take the free bus to all the waterparks such as slide and splash. see all free leaflets for info.
To be honest , get a car you save a fortune and you can take it to Aldi to shop and save a fortune on in resort supermarket prices. Aldi is on the road away from the sea from the fountain, by a mcdonalds and a small shopping centre also worth a quick look.
We were quite impressed with the local bus service. We took a trip to Lagos, which cost us 2.50 euros each. (taxi was 20.40euros each way!) The buses were clean and air - conditioned. They were far better than the buses which were used for the airport to accomodation.