It really depends on the purpose of the trip. I am lucky to have a variety of cameras at my disposal, from the G-1 and GF-1 through professional DSLRs and I still even have my 4x5 camera and the big tripod. For personal travel, the micro 4/3 cameras are a great choice -- my wife and I can share a nice kit with several lenses and two or three cameras, and it all fits in a small waist pack, or just gets thrown in a purse or shoulder bag for the day. A smallish travel tripod with a decent head is fine for these small cameras, too, saving the weight and size of a larger tripod. Image quality is excellent for personal prints up to whatever size I care to make on an Epson 3800.
If the trip is for work, of course, then it's a different story. There are definite image quality gains using a 1D Mark IV or a 5D Mark II, especially for low light work. But then it's a whole different trip.