Earlier quoted context omitted.
Impeachment results in removal from office, not jail time. Jail time could result from further criminal charges and proceedings but if he's been pardoned then no jail time (if the pardon is considered constitutional).
Obviously, Mike Pense would pardon him. Really interesting question is if he we're impeached can he run again?
Pence probably would. Even a Democratic successor might (for some crimes) just because it's more politically expedient than dealing with what would, arguably, be a political prisoner if he were convicted and imprisoned. Again, depending on the nature of the charges.
He probably could. I don't think there's anything that prevents a successfully impeached person from holding office again. It just removes them from office and requires reappointment or reelection. But I think he'd lose the popular vote again and probably the EC since enough people would've finally wised up (or just lost the momentum).