OP might also consider taking RSW-BOS as ticketed, and BOS-ATL immediately thereafter on a separate ticket
another option might be a Same-Day-Confirmed change to RSW-ATL-BOS and skip the ATL-BOS leg
> $75 for a non-status passenger
> not an option for a Basic Economy ticket
> would require same inventory for a coach ticket, but only an available seat for eaither Comfort+ or First Class
> would not work with checked baggage
> yes I know hidden-city is illegal and unethical, but on a one-time basis it might be worth the risk