Question: how many episodes of naruto can i skip?
Answer: Watch episodes 1-56.
Skip at 57-70.
71 - Last 10 min or so is manga material. But is relevant for the next arc.
Pick up at 72-89.
Skip at 90-111.
Pick up or Skip - 112 - Last 10 min or so is manga material. But is relevant for the next arc. ... 
Pick up at 113-143.
Skip at 144-151.