travel between Lisbon and Faro

I've done this drive several times myself and it's easy once you are outside of Lisbon. The E1 Autostrada is about a 3-hour straight shot to Faro. You get a ticket when you enter the Autostrada and pay when you exit. Traffic is usually pretty light, at least compared to most American highways, and there are frequent rest stops along the way with food and gas. See www.viamichelin.com for driving routes and directions. You will need an International drivers license, which you can get at your local AAA office for $15. For car rentals, see www.autoeurope.com.

If you don't want to drive, you could also take the train or bus from Lisbon to Faro. Either takes 3-3.5 hours. You can just buy tickets at the station or ahead online.
Portuguese Railways - www.cp.pt/passageiros/en/
Bus - www.rede-expressos.pt

I encourage you to check out the train. If you book ahead of time ( up to 30 days) there is up to 40% discount. This makes it likely less expensive than driving and so much more relaxing. You could then pick up the car in Faro to use while in the Algarve.

Thanks for responses. Think we'll inquire about train travel between the two cities.

I have done this route many times by car...it is a piece of cake! If your rental car comes with the Via Verde toll transponder, there is nothing you need to do extra. The tolls will be automatically charged to your credit card. Make sure you use a toll lane clearly marked by a huge green "V" on the road or a sign showing the "V". I always use the far left lane which is a Via Verde lane at all toll booths.

I recommend a car as the distances to all the sites in the Algarve can be sometimes far and off the beaten path. All the roads are cleary marked, and with a GPS there will be no worries. The main roads generally use roundabouts. The highway is very efficient for long distances. Hope you have a great trip to Portugal!