I dont know any sites with outdoor tips on them, but I've kept all my chams outside for 10 months out of the year and its great for them.
A few tips, make sure the cage is a decent hight off the ground, mine are almost 3 feet off the ground, close to the ground is just asking for wild animals to try and get in. If you have alot of wild animals I'd put a strong chicken wire or something of the sort outside of the cage to keep him safe.
Make sure he has lots of foliage real and fake. it gets real hot here in FL and mine like to hide and cool off alot as well as bask.
Dont put the cage by an aluminum or metal shed...that should be self explanitory.
with outside cages I like to set up misters to run several times a day and I set up drippers that run for 4-6 hours a day...plenty of water for them...I LOVE KEEPING THEM OUTSIDE..SO DO THEY 
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From Sunny Florida
Jovana's kids listed below
1.0 Veileds
1.1 Ambanja Panther
1.1 Tamatave Panther