I can't answer your second question, unfortunately, but can advise checking the breeder/dealers/stores list on the main kingsnake page (a link is also above on this page, with the others).
As for cleaning rocks and wood:
Rocks should be washed and scraped (an old toothbrush works great)to remove dust, dirt and any critter eggs that may be stuck on them and plant matter (if it's a river stone, their can be algae etc). Then soak it in a bleach/water solution for a couple hours, rinse well and let air dry. Wood can be baked in the oven for about 2-3 hours at about 250F, or if too large or unwieldy for the oven, soak in a bleach/water solution for several hours, rinse well and air dry for about a day.
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PHLdyPayne