That would be a nice way to do it if the online guide showed the GPS corners, which it doesn't, it only shows the center of the claim which is useless for telling where the boundaries are. There are very few signs on the ground for claim markers, often even if they are there they are at the corners, not where you enter the claim. Neighboring claims will sometimes have signs saying NOT A GPAA CLAIM to alert you.
You have to join for an annual membership and get the actual printed guide in order to get the GPS coordinates. Then check online to see if that claim is still an active claim for GPAA. Then enter them in your GPS program of choice, I like OnXMaps.
If you are a member you can try joining the unofficial GPAA Facebook group and seeing if someone can message you the coordinates if you don't have the printed guide. GPAA will not post coordinates in the forum.