Yup, you need a bedroll, your horse (of course) and your trusty Winchester carbine (to shoot the claim jumpers). I don't think we'll be panning so you can leave that stuff home. And, the mountain is so full of gold, your metal detector will just be going wild about the time we hit Murphy, so you don't need that, either. Everything is informal (NO TIES - if you wear one, we'll string you up with it, pilgrim)
Seriously, outdoor clothes, good hiking boots and maybe a light jacket was all I needed last year. I just looked at the forecast and it looks like high 70's to mid 80's in the afternoon, with mid 50's at night. Of course, up on the mountain it will be cooler.
I should add that TanMan was wearing his (garish) sport coat and tie at the SHM, but got reasonable on Saturday...