Firstly, late August/early September is still a long way ahead. The economic crisis is biting in teh Algarve with higher fuel prices etc.
Most of the private tour operators are small businesses so I cannot guarantee they will still be in business by the time you come.
I do not personally recommend operators but the following are companies that have been used or recommended in the Tripadvisor.com Algarve forum.
Algarve Jeep Safari - http://goo.gl/hKmAb
Followmetours - http://www.followmetours.net/tours.htm
OwnersinPortugal - http://goo.gl/pJfi8
"Comment on OwnersinPortugal from contributor on Tripadvisor"
" .... I found this on the internet and booked two day trips with Alan Sutton last year when we were staying in Albufeira. We found him to be very friendly but professional and a mine of information. You tell him what you would like to see and he can add in suggestions of things which you would probably not know about. The beauty is that you set the pace of the day, spending longer in places that interest you and moving on faster if something doesn't take as long as expected.Alan points out things of interest throughout the journey in his up market Citreon picasso with tinted windows, air con and cooled water. He also takes you to some great local cafes/restaurants depending on what sort of place you would like to eat at.
He picked us up from and returned us to our villa in Albufeira. We had one tour going west, up into the mountains of Monchique and visiting Silves and the highest point, along the West coast to Cape St.Vincent and back via the South coast passing through Sagres and Lagos etc. The second tour we went East, stopping at Loule and visiting the market hall full of local produce, Faro old town , Tavira and Vila Real de Santo Antonio at the Spanish border. These towns were all very different and the area is much less commercialised than the central Algarve.CAn thoroughly recommend these tours and We will be booking further tours with Alan when we return to the area. "
As regards where to stay, Albufeira is very central but very very touristy. If you seek somewhere more Portuguese have a look at either Tavira or Lagos.
