He went to Japan, married and became a rice farmer. You can visit his grave in Shingo, Aomori Prefecture.

Pretty sure he'd be the hermit in Monty Python's "Life of Brian".

Jesus vs The Rock, let's make that happend WWE!

Well the biggest contributing factor would probably the fact that Judea was a hotbed of insurrection and Revolt at the time. That he himself was a feature of that setting. Within his lifetime his homeland would have been at war with Rome. So I doubt he lives to old age.

According to Christian lore, he ascended to heaven and is still living.

If he was to be living on earth: He would have continued to proclaim living a life of peace, forgiveness and true Godliness. ("Go and sin no more.") Many potential followers would still have been pissed that He wasn't militaristic and the Romans would have been pissed that he didn't fully submit to Caesar/Rome.

Maybe he would have lived long enough to make sure all the gospel writers were on the same page. The phrase "gospel truth" is very ironic in its usage.