I don't know if there are materials that talk about the RIAS subtests, but I guess that I wouldn't worry about knowing what they are ahead of time. I did find it useful to know about the subtests of the WISC after my dds had taken it so I could better understand how they scored and maybe why. But, ahead of time would have done me or them no good unless I intended to prep them which, as you mention, isn't your intent.

Study Strategies for Accelerated Learners