Originally Posted by
MSPeconomist
It's hard to answer without knowing the timings.
It might make sense to use MARTA to leave the airport area and go downtown, to the art museum area, or even to Buckhead. Moreover, if you plan to visit the DL museum, you should pick a hotel that would be convenient for it.
Plane train is airside, so it might not work for you if there are checked bags.
It doesn't matter whether OP has bags or not. If you have checked bags and go in the "domestic" entrance (where the SkyTrain drops you off), you go up to the "domestic" DL check-in desk as you normally would. This set-up is only a problem if your international carrier ex-ATL is someone other than DL/AF/KLM and as a result the airline in question doesn't have a kiosk in the domestic terminal.
But OP is flying to PLS so safe to assume OP is flying DL the whole way so it's absolutely fine to check bags at the "domestic" entrance and then take the airside plane train to E/F for actual departure.
If OP is just doing an overnight the absolutely easiest thing to do is arrive, head to domestic baggage claim, take the SkyTrain to one of the Gateway hotels, spend the night, take it back in the AM and check bags back in at the "domestic" check-in and then go airside via Clear/PreCheck and take the plane train to E/F.
ATL is a nightmare if you need to be picked up by an actual airport shuttle or car / uber / taxi -- so the SkyTrain and Gateway hotels allow you to completely avoid this.