The closest RTC bus stop is about five miles north: the weekday 110 (Eastern Blvd route) that only goes so far as Horizon Ridge @ Eastern.
RTC Route 110 and here's the
map showing where the car was, versus the end of the weekday 110 route.
Did he walk five miles and try to catch the bus the next morning (about the time his phone checked the voicemail?) It could be a possibility. He could easily have found an RTC transit route flyer. But walking five miles, after heading the wrong way up EL, seems kinda odd.
If a taxi was arranged, he wouldn't have had to walk that far to meet it. They come right to the address you specify.
What brand of copy place is that, that has mailbox services? Did you check to see what their requirements (ID, prepayment, etc) were for renting a PO Box?