I find lists to be very helpful. If you're like me, when you drive away you have a nagging feeling that you forgot to turn something off and you will returned to a pile of ash instead of your house. Making a list of everything to do before you leave, like checking the doors are locked, lights are off, oven turned off, etc... is helpful and guarantees your piece of mind when you pull out of the driveway. One thing I like add to the list is turning the water heater off or turn it to vacation mode which is a setting many new water heaters have.
Another list that is helpful is what to pack. You don't want to have to buy a bunch of stuff you could have brought with you but forgot. If you are addicted to coffee like I am you may want to pick up some Starbucks Vias (Starbucks version of instant coffee which is in my opinion the best instant coffee) as the person you are staying with may somehow not be addicted to coffee. Having a packing list is also great to use when you are getting ready to go back home so you can make sure you didn't leave anything behind.
A GPS is a must have. If you are still resisting this technology, give in. It's like resisting the cell phone, it makes life so much easier so often. I find even if you know where you're going on a long trip it's better have a GPS so you don't have to be constantly aware of which exit you're at. If you have an Android phone you've already got a great GPS.
Another good thing to have is a laptop, but even better is a laptop with a phone you can setup as a hot spot. If you have at least Android 2.2 you can turn your phone into a wifi hot spot by going into the wireless settings and turning the hot spot option on. If not you should be able to upgrade your OS by downloading it online and installing it via USB.
Here are the lists I use. You may find stuff you didn't think of, or if you have stuff you think is important that I don't have on the list, please e-mail me.
Things to do before I leave:
Car tire pressure is full.
All windows are closed.
Blinds are open so plants can get some sun.
All doors are locked.
Oven and burners are off.
Garbage has been taken out.
Air Conditioner/Heater is adjusted correctly.
Water Heater is off.
All lights are off.
No water is running.
DC to AC adapter in car.
Things to pack:
Multitool
x pairs of shirts
x pairs of pants
x pairs of underwear
x pairs of socks
At least 2 pairs of shoes
Toothbrush (In toothbrush travel container)
Toothpaste
Shampoo
Conditioner
Deodorant
Q-tips
Floss
Electric Razor
Cell phone charger
Laptop/Laptop Charger
Good book/Kindle
Instant Coffee
Notepad
Pen
Multivitamins