I seldom travel with anything more than an iPad 2, 64GB and thus far, have gone up to a month and cumulatively, over three months in my travels.
On two multi-week overseas trips, I shot more than 30,000 images and with my workflow, haven't lost any images though I did have a hard drive fail on the last. No big deal since I had two other full copies and a third copy of key images on the iPad.
The problem I found with traveling with a Macbook, besides weight and size, is that I'm spending too much time fiddling with my photos when I should be out shooting, enjoying the experience, sleeping, etc. I use the iPad to directly download key images from my cameras, to prepare images for updates from the field (mainly Facebook and email), show the images to colleagues, friends and locals, use as a portfolio and my credentials for access in certain places and to show and educate locals about who I am and where I'm from. It also serves as a last-line of defense back-up of some of the key images.
My iPad's great for taking notes and with a pretty-good built-in camera, also gives me another back-up device in a pinch!
During a month in the Balkans last fall, I spent more time shooting, relaxing and enjoying my trip rather than deal with images. There's plenty of time back home when the clock isn't ticking on expensive travel! I simply break things down and edit in smaller chunks when I'm in my studio.
Because cards are cheap, fast and large, no need not to have plenty to do an entire trip, especially since they are also pretty durable, small and light-weight. To back my cards which are used but once during a trip, I use a pair of iPad Hyperdrives with built-in card readers. A card gets backed to one, than to the other and is then retired for the rest of the trip. Never had this luxury during the days of film! But on the other hand, during a TV interview in Serbia, the producers needed some of my photos from both this trip and others to feature during the broadcast. Though it was a little slow processing large & raw files, simply using iPhoto on the iMac did the job. Not fast, but totally useable and I delivered.
Both the iPad and Hyperdrives last for hours on a single charge and can be plugged in to a USB socket for charging. The Hyperdrive can also be charged from AA batteries with an inexpensive pack.
For the iPad, there's an app that will dovetail into LR and into which you can work your metadata and boiler plate.
However, on the flip side, now that I'm working as though I'm shooting film in the field, I must deal with the metadata and processing once I get home. Sure, it takes days to do it, but so did processing, editing, labeling and distribution of the transparencies.
As I tell my interconnected friends, the timeless quality of my photography waits as I'm the anti-Instagram of photography!