After a camping trip/expedition, I noticed a lot of places lacked the resting script or whatever would allow resting. For example, one happened to be inside abandoned buildings or caves.

My suggestion is to make nearly all of these places restable unless there's some sort of reason why not to that I'm missing.

Give specific areas. I'm not about to check 300 areas to see which ones have them and which ones don't.

I agree on this. One of the first quests I did was a delivery mission that took me to some mines by Dark Lake. There is a section of abandoned mines that are quite extensive. Why exactly can't I sleep in an old mine even if the 5 hour minimum between rests has been reached?

I'm new but I thought I'd add my 2 cents.

Have never had this problem myself. But then again I am a ranger and do not need to "set up camp" to rest. Luck me :) It could just be something with the camp fire things. I know my friends have had trouble with before while I can just rest right on the spot

Now I'm confused. You first need a bedroll (as a non-Ranger/Druid) and I understand that you need a campfire, but what is the purpose of the rations/food?

Food and drink are pure RP items that have no actual use IG. Areas that allow campfires need to be specifically tagged to do so. Some areas might intentionally not allow it, while others just are missing the variable.

The first area beyond the dark lake by boat, outside the lizardmen city, is also not tagged for resting. I guess it should be, as it is little different to the Sanctuary gates, where it is possible to rest.