Four countries, 17 nights, one Tumi international carry-on and a backpack. Your advice?

Update: Returned from our travels with this updated review... Review: Excellent Tumi Alpha 2 International Carry-on fits 17 days of stuff into the overhead bin

Next week we depart on a journey through four European countries -- Spain, Portugal, the UK, and Sweden -- that will take us from the city streets of Madrid, Lisbon, London, and Gothenburg to the wine country of Ribera del Duero, Rioja, and the Douro Valley. I'm at the end of my rope with the magical shrinking airline carry on, so have decided to boldly shoehorn 17 nights worth of kit into a Tumi International 4-Wheeled Expandable Carry On suitcase and their Knox Backpack.

This is happening, and this weekend is the pack test when we see how much we can cram in here. Complicating matters is that we'll swing from high/low average Fahrenheit of 78.8/57.9 in Seville, Spain to 45.9/37.8 in Gothenburg, Sweden... and I'll need a tie and jacket for an event in London.

So what say you? Any recommendations or packing tips as we take this on? What works for you?

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