A question.
Let us assume someone traveled to ID with at least that phone.
If PF, or anyone else involved, has made that trip to Gooding area, he most certainly traveled along major highways, I-80 and I-84.
A person should have filled in his gas tank. Probably before the trip in Colorado, and then somewhere on the way.
Either the credit card should reflect the gas sales, or if a person paid cash, usually in not so densely populated states, the strangers are noticeable. The person should have either eaten somewhere, or bought something at 7-11 when filling in the tank. I doubt that someone brought the tanks with him. If he did, there should be some stain where the gas tanks were?
In short, is there a way to check cameras or even ask owners of gas stops? Logically, if I wanted to be unnoticed, I'd use major highways and pay cash, but even in these case, someone might remember CO plates. Flyers along the highways? Of course a person might have used a smaller gas station off the beaten path, but rural folks would be nosy.
Another way to get gas unnoticed would be Costco gas stations, this is a possibility, lots of people going through, and there is a place to eat there, but Costco has cameras. I wonder if Costcos along the way have been checked?
Another issue, 1600 miles means one needs to sleep. Either a motel but again, rural folks remember strangers, or drive at night, and sleep at daytime at truckers areas, in the car (forgot how they are called. Where truck drivers might have rest). Has anyone checked those locations? Some local truck drivers who would regularly travel along that route and might remember a guy dozing off in a car with CO plates?