I applaud your motives, & I hope it turns out as you imagine, but a word of caution: years ago I adopted an unwanted yearling BCI, & while I wouldn't trade the
experience, you should know that she had changed homes many times before she was given to me, because each new home made her more fearful & better at
biting & turning off owners.

Had she been exposed to other illnesses or mites during that time, her health could easily have suffered, since stress is no better
for snakes than it is for us...but I got lucky (as did she)- I got her in time, & I turned her around (she quit trying to bite) but it took patience with no guarantee.
There is no one "right place" to find such a snake...it comes down to word of mouth, local ads, luck...let vet offices, pet stores & animal shelters know you're what
you're looking for, check online re-homing services in your area (like PetFinder). Another good place, though probably higher priced, is finding a breeder with more
hold-backs than they want to keep. Check classified ads on forums like ours (or Fauna Classifieds, Kingsnake.com, etc) or post your own "wanted" ad. I once got
some unwanted rat snakes from Kingsnake & it turned out just great for all concerned: the owner lost his job & home & had to relocate with a very uncertain
future for the time being, & the snakes were healthy (still are), BUT, you never know.