Dole would probably win the GOP nomination because he was the runner-up in 1988 & it - like real life's 1996 - would be considered "his turn." As real life's 1996 proved, though, Dole is an inept campaigner whose generational warfare rhetoric turned off many voters, & as we saw in real life's 2012, even a vulnerable incumbent President can still win re-election if they're facing a weak opponent. So I think this 1992 would probably be comparable to real life's 2012: either candidate would have a chance to win, but the incumbent President has the slight advantage because they're the incumbent.
I think Kemp would beat Dole in the primaries then win in November including sweeping into power a Republican House and Senate
I'm sorry, I just don't see how Kemp beats Dole in the primaries, let alone wins in November,
let alone does so in enough of a landslide to sweep congressional Republicans into power.