Adult mites can travel like 8ft an hour or something like that, sit & watch one & see just how fast the lil sucker can actually travel.
That said they are likely everywhere already BUT they do tend to stay close to the hosts.
It all depends on how long the place has been infested, anything longer than a day or 2 they should be assumed to be everywhere & EVERYTHING should be gutted/trashed for substrate & fully sterilized as well, all snake enclosures & snakes treated directly of course. Mark