You can practically go anywhere in the game. Even at the top of mountains (if the slope is not too steep).
Only you can't go into deep water but you can still go in like knee-deep water and walk around.
Yes, you can take rest and wake up at any time. This is useful when you are after specific animal and you know their need zones (like drinking zone or resting zone) and you can go their at specific time to find them. Also different animals remains active in different time of the day.