Given a certain context sensitive grammar, can one find out if a simpler context free grammar exists? Given a generating grammar, is it possible to reduce it to a context free form, if one exists. One method might seem to be if the context sensitive rules can be reached from higher generating points, in some sense. However, is this an interesting question worth worrying about? Are there practical situations, where there is some benefit in reducing a more complicated language to a context free language?
No. By Greibach's theorem, it is undecidable whether a CSG generates a context-free language.