Campsite, Aires, or wildcamping.?
What timescale ?
In a hurry or happy to pootle along ? Motorways are mainly tolled and boring.
The RN 2 is a more interesting route south, free and you'll see some of the real Portugal.
Look up Camping cars Portugal.pt
Aires are in all sorts of places, but will be crammed full in high season. The Algarve, especially.
The further south you go, the hotter it will be.
Parking near beaches, will be difficult . The north and interior would be better and cooler.
We first arrived here for Xmas 1999 and never really went back.
The people are generally pro-British and delightful
But all the sharks, near the beaches aren't always big nasty fish.. There are some even nastier humans prowling to take advantage of holidaymakers.
Avoid all the coast between Faro and Lagos. It's more like Blackpool in the olden days.... You could be in any modern resort.
Come down and allow yourself a relaxing journey back.
That's just my current thoughts.
If you need help, we never close.
Boa Viagem.