I'd say the most inaccessible part of New Delfos would be Jidhar Mountains in the south that separate the Kazjko Region from the Mahara Region, from whichever main airport or land-wise it'd take about 1h to just get there, any type of extraction or aid would probably take minimum 4hours to complete IF they know exactly where you are. If there's a mountain accident or a plane crash, it's unlikely you survive in this part of New Delfos, there aren't a lot of people that could even report the disaster, you'd likely be reported missing sooner than anybody finding you out wherever you had your accident.
Another case of this is the Boyen Forest in the north, mostly because it's huge, people don't venture outside roads bc it's too dangerous (being lost, wild animals, easy to have an accident,
bandits as there are dangerous people hiding deep in the jungle), but the rescue could be shorter than Jidhar mountains. The Virit Line Mountain Range is huge too but it's more accessible than the Jidahar mountains and there are major Cities close enough, even if it'd take another hour just to get there, rescue and resources would be greater than in the South. Again, it's more likely you're reported missing sooner than getting a rescue.
The most common use of rescue in New Delfos is the coast guard and navy for ship wrecks and maritime type of emergencies like medical evacuation and that sort. There are some sad stories but you can count on the Delphic Navy for help.
