Well, if you have a grasp of Sanskrit grammar, Russian grammar probably wouldn't overly challenge you. Russian grammar cases are very similar to Sanskrit ones. Most modern Indo-European languages have lost the case-endings system Sanskrit, Greek, and Latin preserved from PIE, but Russian has kept almost the entire structure. Obviously, the details are different from Sanskrit, but the principle is the same, which is half the battle.

And Sakrit might even give you a little more of a vocab head start than you'd have from all the German and French borrowings in Russian most of us English speakers are familiar with because we borrowed the same words. lol