IF I WON'T BE DRIVING MY TRUCK IN THE WINTER THAT MUCH, WOULD IT BE OKAY TO LEAVE THE BLOCK HEATER UNPLUGGED FOR A WEEK OR SO UNTIL IT WARMS UP A LITTLE.

 

i wouldnt but thats up to you if it dont warm up very much its gonna be a hard start thats for sure and when you do try to start it it will be hard on your batteries and starter could end up costing you more for either of them then it does to leave it plugged in

 

Lets think logical:
If you know that you won't drive for at least a week.
Why don't you take out the battery and store it inside to prevent drain and self discharge.
If you think it is to much work to dis- and reconnect the battery just install quick disconnects.
If you know you won't drive around, why shouldn't you disconnect the block heater?
The engine will be heated up again within a couple of hours before you intend to drive again.
Why wasting energy?
A block heater consumes around 500Watt per hour. thats 12000(12kw) Watts per day and 84000 (84kw)watt per week.
You can save that.