Mexico just across the border

I'm starting a photo trip in a couple weeks, from Tucson to Vancouver BC. I'm trying to get information on a specific route out of Tucson. I'd like to drop down across the Mexican border at Organ Pipe Cactus Monument, then follow the border WNW to San Luis Rio Colorado, and cross back over into Yuma.

Basically, I don't know anything about the route: safety, border crossing, services, etc., pertaining to this stretch. Any personal experience or advice would be appreciated. Thanks up front. Rich.