Independent Travel in Europe

One to two months (or more) prior to departure

Find someone to look after the house, including plants and/or pets, while you're away.
If you won't be driving yourself to the airport, arrange for someone to drive you, or look into public transit or taxi fare to the airport.
Purchase rail pass/bus pass or tickets online, if required.

Two weeks prior to departure

Confirm accommodations
Confirm auto rental
Confirm arrangements and leave house key with person who will take care of the house.
Check long-term weather forecast for arrival destination.
Purchase foreign currency (enough for a day or two; if you need to pay your first vacation rental in cash, make sure you'll have it on you)
Valuables in safety deposit box (if necessary)
Document itinerary and send a copy to family/friend
Ensure that ATM card(s) will work in Europe (check with your bank)
Use each ATM card once before you leave to be sure they are all working.

Contact credit card companies to let them know that you'll be travelling

Return all items to public library and cancel or suspend items on hold

Postal service: if nobody will be picking up your mail, arrange for
 post office to hold your mail while you are away.

Arrange to suspend newspaper/magazine deliveries.

E-mail account: Arrange to know how to access your e-mail while you are away, or create a webmail account.

Create copies of documentation (passports, driver's licenses, etc. see Packing List) OR Scan & upload copies on a USB stick.

Three days prior to departure

Call airline to confirm flights. Read all pertinent e-mail alerts
Request special in-flight meals if you haven't already done so.
Check short-term weather forecasts for arrival destination
Confirm ride to airport, if someone will be driving you, or know public transit routes/schedules, or have phone numbers for taxi companies on hand
If you're driving to the airport, plan the best route given the time of day and/or possible delays
Start packing your suitcases
Prepare luggage tags and attach to luggage
Bank account: make sure your account will have enough funds for all the withdrawals you will be making while you're away
Review packing list

Day prior to departure

Make sure everything is packed except for items you will still be using the next day
Go over your packing list
Prepare travel wallet and money belt
Answering machine (change message if required, otherwise just make sure it's on)

Day of departure

Garbage/recycling out (or arrange for someone to take care of it)
Empty the fridge
Turn off water
Program timers for lamps and TV
Unplug computers
Unplug appliances
Pack remaining items
Lock windows and doors
Get on the bus or in the car/taxi and go to the airport :))