If you are using the CP that's great. I have an old WN standard award (expires 10/15) and a CP I could use too but no one else to go so I'm saving it for something with a companion to a central america.
Since availability is really scarce I don't think a long stopover in PTY is possible. If so I'd go because I can get free nights in PTY through IHG. But a day and a half is a long way to get to Brazil when United has non-stops to Sao Paulo of 10 hours from here.
Mexican rules would apply and I don't want to chance a mistake fare last-minute mess-up.