Which did you prefer? Glen Helen or Mammoth?
I don't know, they were both very fun. Mammoth is inland and up in the mountains and has fantastic scenery in the mountains. We flew into Reno, NV and drove from there to Mammoth Lakes. The track was really fun but not really like a National track.
GH we flew into San Diego, rode a day at Pala, went to Laguna Beach and walked in the ocean, got stuck in LA traffic after and felt like shooting myself in the head. I remember exiting the highway to another highway simply to get out of the traffic, I didn't even care where it was taking us. Riding at Glen Helen was very intimidating.
I would love to do both again and am glad to have the memories of doing it.
Kind of a funny Mammoth story --- I don't remember what we paid the dude to drive my truck out there but we gave him half the money when he left and were supposed to give him the rest when he got home. He called us from Reno before we flew out asking to bring the rest of the money because he lost it all gambling and didn't have any money to buy food or gas! It was him and a friend that drove all the way out there basically non-stop trading off driving and sleeping.