The only real fix I have found for this is the DM simply forces the player(s) to keep playing the game.
There is no amount of mechanical rules that can help if the player(s) are dead set on "resting all the time". The players will just follow whatever rules they have to, and won't care about what the DM says or does. And will out right call the DMs silly bluff of "oh the world keeps turning while you rest", but the players KNOW the DM will never alter the game to be out of the players favor.
Example: The players attack a dark tower full of foes. At a point they whine and run away to rest. They rest for a time...then come back to attack the dark tower...again. The DM can bluff all day long about how the tower is now on "high alert" after being attacked. But the tower door guards will STILL be exactly TWO "appropriately fair and balanced by the rules encounter" foes. The DM will NEVER have six powerful guards and do a TPK on combat round three.
More Extreme Example: On round five of combat the players run away from a dragon to "rest". The DM blinks and then says "oh, um well, you give the dragon a free attack as you just walk away" and gets ready to do an attack. The players just shrug "whatever DM, go ahead and kill our characters and end the game and we will just leave and not come back". The DM looks on with horror about being abandoned and just says "er, um, oh, the dragon watches your characters leave."
Being the Hard Fun DM is the only way to stop the "rest all the time players". Though more then likely such players will leave that DMs game.