Well, I thought the same thing you did, Heath, that he would need a pardon from Pence or whomever took over as president. I'm not a brilliant legal scholar though, but Andrew Weissmann is and he believes Trump will self pardon. Basically it seems questionable if this can be prevented according to Weissmann and the issue is just that we've never had a president that would be shameless enough to attempt it...now we do. Trump cares nothing for rules, laws, and certainly not accepted standards and customs. He wipes his ass with the Constitution on a regular basis so, if he thinks he can do this, he will do it. 

Here's the thing I think that Trump does not understand about a pardon, it is not just a get out of jail free card and it does not mean you are innocent...acceptance of a pardon is actually a tacit admission of guilt and so by self pardoning he is admitting he is guilty. Also he can only pardon himself on federal crimes, not state, so this does not save him nor his dirty family from the SDNY.