Onebag.com is an amazing website all about how to pack for a trip - any kind of trip for any duration. Their packing philosophy obviously all about traveling light. The great thing about the website is they tell you how to achieve taking only one carry-on size bag on any trip - not just why it’s a good idea. Better yet the author is Canadian - represent!
I did a practice pack last night and managed to fit everything I need for my four week trip into my 30L bag with plenty of room to spare!!