Sounds like it's a case of the Grass is always greener..... or Astro in this case (boom boom)!
Everyone i know here loves the idea of racing on Clay as to be honest i think the cars are designed for that really - obviously they're tuneable to the point to make them work really well on Astro / Grass / High grip but personally i think a 2wd buggy really comes in to it's own on Dirt with big flowing jumps and elevation changes and anyone that's raced on it tends to love it!
I think the U.S guys would like Astro/Grass if they got used to it and i can understand wanting to try it as a change but overall it would be quite expensive to do for one meeting surely? I think the main issue would be you finding tyres that work - I can imagine Schumacer / Ballistic RC in the UK getting a huge order if you do go for it
There aren't really any Proline, JC or Losi tyres that would work so it's worth checking that sort of stuff out too.
Are there any artificial playing surfaces you could try a car on? Aren't the American football pitches often Astro? Maybe get someone to send over some tyres for you to try and see what you think of it first?