How long does it take a letter to travel 1000 miles through the mail?

I want to time an arrival just right, does anyone know how long it would take a normal letter to travel 1000 miles if stamped and dopped into a mail box? Mailing from southern california to oregon.How long does it take a letter to travel 1000 miles through the mail?Air or Ground. There are too many variables to answer this question.How long does it take a letter to travel 1000 miles through the mail?1000 MILES?