Regardless of where you choose to get a claim, you will still have to test the site. Placer, hard rock - anything.
Look up historical mining documents in the area(s) you are interested in. You're looking for placer, so go through the old literature and watch for areas that were mined in decades past. There are areas that will read as being mined out - no more gold. But remember, much of your literature is coming from some government reclamations department. They WANT everyone to believe that there is nothing else to find. Keep these 2 thoughts in mind:
1) gold recovery now is MUCH better than it was 100 years ago or more
2) ALL gold mining was stopped in the past due to WWII, and by the time mining was again allowed and gold prices rose, there just wasn't as much interest. So there ARE places out there that still have gold. Also, gold is more likely to accumulate where it has historically. So for you, my friend, homework! homework! homework! Read until your eyes are ready to burst, then read some more! There's an awful lot of history out there.
When you find prospective areas, look them up on Google Earth and study the maps. Pay attention to water sources (past and present), snow melt, the buildup of modern civilization. Try to compare newer mapping to old, historical maps. Learn which rivers/creeks have had a course change in the past 100-200 years.
There ARE respectable gold claims sellers out there. Many people are more interested in doing the research and finding areas that are likely to still have good values, then they sell these claims for a hefty profit. But, the good ones "earn" that pay by doing the research for you. Still, trust only your own sampling and tests. If you don't find good results, just remember that it "could" be because you're missing a step, or not thorough enough, or any number of other reasons. If gold was easy to get (in quantity), then it wouldn't be worth squat. But unless you have some deep pockets, you would be best served doing your own research and your own testing.
Finally, study the claims of the past. Read about their equipment and procedures; what they did right and what they did wrong; what problems they encountered along the way. Better to learn from past mistakes rather than making them all over again.
Good luck!