Some of the Air Mike flights are hard to even buy full fare seats on, let alone non-rev on them. The Honolulu Hopper is a classic example.

It seems like you may be coming from the U.S.A. given the ex HNL price for the pass you gave - going the other way may be a better bet.
If you can get to GUM, (see below) then there are bound to be GUM based agents on the www that will have bulk/wholesale cheapie deals on Air Mike from GUM to both Truk and Palau as seperate returns.
CO's website is showing these flights at about USD550.00 return each including taxes, so agents should be able to do better. More so with as much advance notice as possible.

If you're having trouble getting a nonrev agreement to GUM using Air Mike, then look at the other side of the Pacific and check your interline/zed agreements with JL, NW, OZ, KE, CA and probably others who all serve GUM from the far east. Some carriers may even serve Palau direct from the far east as well.