In my experience of having learnt Sanskrit via what I now realize is the comprehensive input method (thank you for introducing that term to me via your comments on this thread), I absolutely think that the "basics" - enough to recognize the seven (eight if you count the sambodhana) vibhaktis (declensions) and the simple past, present, future and the subjunctive tenses - are required in order to get past the huge roadblock of parsing a word.

Once parsed, I can look up the meaning of the word on ashtadhyayi.com or elsewhere, but not before.