@hong
I remember resting was a thing to consider in the countryside when traveling-exploring and in dungeons when exploring.
Certainly. This is why you make sure to double back to already-cleared areas before resting.
Anyway, you are suggesting that a 4e video game should not have any resting. I am not sure about that. You do realize that you have to have a structure of some standard variables tied to exploration to make a game open ended gameplay wise and not browsing wise right? Does 4e has enough of this? It has more than enough on the tactical side of things, on the tactical combat map but not out of it.
If you mean that there has to be some constraint to keep exploration tense and exciting, rather than simply a string of fights where the PCs are always at full strength, then 4E already has that. They're daily powers, magic items, and healing surges.
What I might do to replace the half-hourly fade to black is replace the "per-day" recharge mechanic with something a bit more fine-grained. Maybe a daily power recharges every hour, with each power having its own recharge meter. Maybe you could have storyline-defined super-milestones, where you get back all surges and dailies. It's not hard to think of alternatives to the conventional per-day mechanic.