I would imagine that Ronald Reagan's Presidency would have turned out the same as in RL if he picked Gerald Ford as his running mate. A Dukakis-Ford race in 1988 would have been interesting to see as well. I doubt that Ford would have ran an aggressive campaign like George H.W. Bush did in RL, so Dukakis could have very well won the election.
If Ford remains on the ticket in 1984, I doubt he would have run in 1988 (at 74 years). Likely Secretary of State Poppy Bush would have been elected anyway.
Ford insisted that Kissinger would return as Secretary of State. Reagan's rejection of this was the main reason he wasn't picked. But it is possible that Bush would had been involved in any postion and Reagan's successor nevertheless. Ford may have run in 1988 and serve just one full term. He would have been term-limited in 1992.