UK,
You made it. I don't know anything about Moses, but I know about Potholes (which happens to be connected via the Crab Creek spillway). I would try calling Mardon Resort (they are on he web) which is located at the South end of Potholes Reservoir. They have accommidations, rental boats with engines, tackle and all the advice you will need to fish that lake. I don't know about carp fishing, but fall is an excellent time for large trout, bass, other panfish. Walleye fishing is another option. Good luck and let us know how you do. Also, your timing here in Seattle is perfect. The silvers are starting to show in numbers and local fishing should be great for the next couple of months.
JMS