Ok, let's take a look at some things here (yeh, time to do some scalation checks)....let's look at all the species that share similar colour and shape. If it's a whipsnake, Masticophis sp., it will have a divided anal plate, and it's scales will be smooth and in 15 rows. If it's a Brown vine snake, Oxybelis aeneus (the only native species), scale rows are 17, only two postocular scales, 8-10 upper labials, and no loreal scale (didn't find info. as to whether anal plate is single or divided....hard to find good scale info. on these guys, since they just barely enter the US). As for the ribbon, it will have a single anal plate, scales that are keeled in 19 rows, 7-8 upper labials (two touch the eye) and three postocular scales. Figure let's find out what genus it is and then we can work on a possible species and subspecies.
Roy