What is the current level of evidence and consensus in the field about the RNA World Hypothesis? Are there promising ways to find hard proof on the topic?

I think the best word to describe it is tentative. There is so very little direct evidence, but there are broad hints, like the RNA machine that is the ribosome, as well as experiments showing that such a world is possible at least in principle. So yes, intriguing and promising, but tentative at best. The main problem is that there is so little information about conditions on ancient earth, and even what info we do have is necessarily broad and general. The kind of chemistry needed to make an RNA world work requires are relatively specific set of conditions, and unless we can be more specific about the ancient earth, I fear these origins hypotheses will always be only tentative.

This website has a pretty good basic summary of the RNA world hypothesis.
http://exploringorigins.org/rna.html