Hi,
If you get down as far as Lisbon, go and stay (wilding) at the Barragem Salamar (Pego Dam). It is just East of Setubal, the Barragem is Horseshoe shaped, so can't miss it on the map. Water, toilets and a shower is available here (free), on the right hand side as you approach the Dam. Lots of Motorhomes here, some for months on end! It's a good stop off point when travelling South. Just pick the right spot for the evening sun! Down by the water is good, fishing from the deckchair/BBQ.
If you stay here visit Lisbon, I enjoyed the Military Museum down by the Dock Road if your interested in that sort of thing, a lot of Portugese history in here.
Enjoy your holiday, we are not going this year

The climate is certainly warmer than here, but gets chilly around 4pm ish.
Happy Camping