T/O
I am based in UK, but fly in AZ and CA as often as I can - but no short-term plans for another visit, so I am very envious!
Whenever I have been there at this time of the year, the weather has been great - no major storms and no hot bumpy flying in the desert.
If you want some really peaceful flying, try Fresno - full ATC, but no traffic and handy for some mountain flying to the east. Also within distance of San Francisco.
In Los Angeles, I use Van Nuys Flight Center at Van Nuys. It claims to be the busiest GA airport almost anywhere, but I have seen Elstree with longer lines at the holding point! They rent dry and you refuel upon return. The overall cost works out about the same, at just under 100 Dollars per hour. Mind you, this is for a new Cessna 172 R or S! I have flown an SP here which had a total of FIVE hours on the Hobbs - very nice and at the same price!
You will obvioulsy have to do a check-ride, so ask them to show you the LAX Special Flight Rules corridor (I believe it has re-opened). Nice way to fly right over the top of LAX legally!
In Phoenix, I use Westwind, based at Deer Valley 10 miles north. An even larger rental fleet of R and S models. They are big on training, so you need to book weekday slots a little more in advance.
PHX also has a VFR transition route right over the airport, though here you are under full Radar control, so a good exercise for the VFR pilot in maintaining cleared heights and headings (and some more good views).
Not sure if you are already familiar with flying in the US, but I now carry my own Renters Insurance (through Avemco). Yes, most schools have cover, but there is this wonderful insurance concept in the US called subrogation. Under this, the insurance company usually pays out, but then scouts around for somebody else to claw the money back from - usually the pilot..........Curiously, I have never seen this mentioned in any UK magazine articles about US flying, but I reckon it could really ruin your day.
If you have flown in the US before, you will know all the differences from the UK, if not post another reply and I will be happy to contact you direct.