New Mexico does NOT have license plates on the front of vehicles, only back.
Early in the movie, we first meet his probation officer waiting inside Dylan's home. But as Dylan drives up, there is no vehicle parked outside. How did his P.O. get there; did he park far away and take a long walk?
If it is winter in New Hampshire, then it is obviously winter in New Mexico. Winters in New Mexico are quite cold. Dylan would not be dressed in short-sleeve shirts during a New Mexico winter. However, some parts of the state can be warmer. For example, the average December high temp in Carlsbad NM is 59, with a record of 85. This is light shirt weather for somebody active. Perhaps the movie is meant to be in such an area.