yeah... I was thinking king snake too...
certainly nothing like a viper.
Pit vipers have short fat bodies, and big wide heads, they don't look like anything else.
I'll post picture(s), unfortunately I don't have anything but rattlesnakes photographed... and, you seldom see them stretched out...
unlike a cottonmouth or copperhead...
king snake
I do have this pic of rattle snake...
observe the fat body...
Here's more typical of how we normally see rattlesnake... observe fat body... and... unfortunately, the head pretty much blends into the body... and takes studying pic to notice...
Personally, I value my rattlesnakes... I take pictures and lock up cats... otherwise... I might lose both... can't teach the cats to leave the desirable animals alone.