At any rate, I don't expect Perdue's campaign to deviate much from that, until or unless they believe that there are no gains to be made in the suburbs. They more or less ran a persuasion-based campaign in 2014 and I expect that is what will be done in 2020 as well (increasingly - though maybe not by 2020 - they won't have any other choice).
What do you think the playbook will be for the GOP come 22 when Isakson retire and Kemp has to run again?
I suppose it depends on how well/poorly Perdue does in the suburbs, whether or not he wins re-election, and who's in the White House. It's a simple mathematical reality at this point that there isn't
much more that can be squeezed out of most of rural GA (and my belief is that most of what they can squeeze out of there will come organically, with or without GOP campaign efforts there, and depends just as much on who the Democrats run). If/once you're maxed there, you
have to turn to the suburbs if you want any chance of staying in the game. Kemp basically milked every drop of vote out of the southern half of the state and still only managed to avoid a humiliating runoff by 0.2 points (the fact that his opponent was a polarizing black female basically offset the lower turnout dynamic the GOP would have otherwise faced during the Trump era).
2014 really stuck out in terms of how they treated rural and suburban areas, and was arguably the first preview of a swing state future. Both Carter and Nunn were considered the first viable Democratic candidates in a long time: both the Dems and the GOP believed this, whether it ended up being true or not. As such and due to a Dem being in the WH (likely believing GOP turnout would be high regardless), the GOP really focused on persuasion to mitigate any potential worst-case scenario and cut Dems off at the pass. The difference in 2020 is that persuasion will become an absolute necessity given higher Democratic turnout and six years' worth of demographic shift.
I expect Kemp to adopt a completely different persona for re-election; he was never
actually an extremist at heart (though he played one on TV) and since winning has seemingly tried to keep out of controversy. Deal wasn't exactly popular in the run-up to his re-election but managed to win given the lean of the state and the partisan climate + finished his second term out with 2:1 favorables. That's probably
his '22 playbook (which will be similar to Perdue's in '20, except Kemp will want there to be a D in the White House), but a brand new candidate seeking to replace Isakson...who knows.
Of course, the flip may happen so quickly that playbooks won't even matter. It doesn't matter whether
Democrats Republicans nominate a moderate or a conservative, focus on rural areas or suburban areas, or engage in turnout or persuasion in a state like VA. The first prominent GOP statewide candidate in GA to lose will also likely be the last GOP candidate to win; that's why staving off any Democratic victories in GA for as long as possible is important for the GOP, and why they have to focus on persuasion (and therefore the suburbs) above all else.