Hello Cal,
Be prepared for an uphill battle or two!
Certainly some types of pamor are more difficult to forge than others - thus, they come with somewhat higher esteem. However, they are also much more easy to mess up during forging work: All other things being equal, a keris with badly done difficult pamor is much inferior to a keris with perfectly executed "lesser" pamor!
Moreover, even quality pamor is more like the icing on a cake: the garap of the blade is much more important. Quality (as judged by the originating cultures) may vary from island to island; it will also vary from quality as perceived by international enthusiasts; again different from the taste of tribal art aficionados, much less the general collecting public...
Do as much reading as you can first! Here are some classic threads:
http://www.vikingsword.com/vb/showthread.php?t=3938
For sure, this forum provides more info than any book published in English. So make sure to review all threads (don't forget the older forum!) sooner or later. This will answer some of your questions and spawn lots of new ones...
Scrutinise as many keris as possible: Don't focus on recent pieces of questionable quality (e. g. the bulk of ePray offers) and make a special point to look into older pieces (musea, etc.) but also note that subpar pieces have always been produced or rather that highest quality has always been the exception rather than the norm! Pics can help as a poor substitute for the real thing but keep in mind that they can also be very misleading...
Personally handle as many keris as possible!
While there are certainly knowledgable folks in the US, I don't know of any dealer with specialised keris knowledge out there. Even if there were any, it would still boil down to caveat emptor! Your best bet is probably to team up with a forum member and to discuss future purchases via email. The more you invest into your own education though, the more costly errors you may be able to avoid!
Regards,
Kai