Hey dude, you are totally right about the simplicity of Indigo,
because Indigo is a unbaised renderer it simulates real light,
so you simply can't do anything wrong it will always look real ^^
You still will need a good setup, just like a photographer...
The only functionality that isn't very easy to understand and use is SSS & Dermis/Epidermis stuff
in the 0.7 test builds, but its still in development...
I don't know how much Rino+Indigo Users are out there who can help you.
If you are used to blender or own C4D, Maya or 3Dmax try your first steps there because of the bigger community.
In your case I would just start with latest stable 0.6 version, rendering a single Object,
covered with a NK material (for perfect physical correctness

) of a metal like gold silver etc. in a cornel Box using BlackBody light
to get some feeling for the results....
after you learned how to setup your 3D App for Indigo Export,
just try some more complex Scenes you did before to render in Indigo.