Mailing from coast-to-coast sounds like it would take a long time, but there are regular flights cross-country, and the sorting facilities bring mail to the middle of the coast, and then ship it straight across, east or west, depending. This means that the mail has to go first to a central sorting facility.
Truck and bus drivers must generally take a minimum of eight hours off between shifts, and their shift hours are often capped. Airline pilots are required to have 10 hours off between shifts to allow for transportation and rest time.
The law requires six hours of work before you have to take a meal break. Therefore if you are working six hour or less shifts your employer does not have to give you a lunch break. Checdk on the postings in your employee lounge. For a regular 8-hour work day, you can usually take a meal break a minimum of three hours after your start time, up to about five hours after your start time.