Post Office question (anyone traveling to the US from Conce)

I'm trying to send a small letter to a lady friend in the US who needs a pick-me-up. The problem is that Corerros Chile will take one month and DHL, FEDEX and Chiliexpress all want >40,000 pesos to mail it.

I was wondering:

a) if anyone had any other ideas on how to mail something to the US that didn't either take forever or cost a ton

or

b) if anyone was leaving from Conce this week for anywhere in the US and could mail this letter from the US. Happy to compensate for the hassle

Thanks!