First thing I would do is check with the MSA what the license situation is for US nationals racing in this class.
Once you’ve sorted that out call the C1 team and I’m sure they can put you in touch with a few reputable “arrive and drive” operators.
Hope you have fun.
MSA contact details
Tel: +44 (0)1753 765000
Membership Services Team (direct): +44 (0)1753 765050