Dumb question about addresses... please let me give a quick example??

Just the PO box is ok. When both are used the PO box overrides the address. The street address is there just in case you are sending something using a company other than the USPS.

ɦəlʞɹɐq

1. Begin by writing the sender's name and/or the company's name on the first line of the address.

2. Add the sender's street address (include Ave., St. or Blvd., as well as apartment, office or suite number) or post office (P.O.) box number on the second line.

3. Print the city name followed by a space, the two-letter capitalised state abbreviation and the ZIP code (five-digit or ZIP+4) on the third line.

4.Include the country name, if necessary, in capital letters on the fourth line of the address.

5.Print the mailing address (the destination address) in the center of the envelope or package, putting each element of the address in the same order as above.

Your example is exactly how the address should be written. Good job.