Well, as you have seen, it's a lot drier...but up there you do have a few more seasons than the lower deserts. It gets much colder, so you have a few more options with stone fruits than the lower elevations, but have more difficulty growing the more tropical plants (not as many varietie of citrus, Bougainvillea, many palms...)

You do have the same alkaline/caliche soils as the rest of us...as for adding stuff in the ground...I bury kitchen scraps (veg, egg shells, coffee, tea) that way I don't have to worry about a compost pile and it adds nutrients to the soil...You might look at the frugal gardening portion of this site and find some helpful answers there...

Here is a link that might be useful: Yavapai County Hardiness zones

much shorter growing season up in Prescott, you won't be able to grow most of the sub tropicals... you can forget about things like citrus, bougainvillea, mexican bird of paradise, but you'll have success with annuals that do better because of the cooler temperatures.... all the herbs will do ok, you will get more rain due to the elevation!!