I can not overstate the importance of getting your metadata into your images as soon as possible after the image has been taken. Drawing from my experience of long time and long term traveling this is one of the most important thing for any travel photographer.
I have now after spending more or less half of my time on the road in the last 6 years, built up a system that is getting better with every month. When I first started the big trip in the expedition truck Benzi through the Americas I had prepared my self a bit but not fully and by that time I was using Portfolio from Extensis as my database. While on the road Lightroom came out and is now my first choice of tool to work with even though its not perfect.
My procedure is simple. Every night I empty all cards into the computer. Load images in Lightroom. Give them the basic keywords and metadata and then export them as DNG. I keep the dngs on my computer and back them up on external disk. The raw files are either backed up on external disk or burnt to DVD that I then ship home. This way I have multiple backups with and with out keywords, but I also write a journal of my travels even thoug it might only be stack of keywords when I am lazy.
For that I use Evernote today and have that on my computer, laptop and phone. I can therefore take and make notes just after I have taken images and then sync the whole thing later on.
Many times now years later when I have been working on my images from USA and Central America I am thankful for this process. I can easily find my images and in some cases I have had to use the backup from DVD that I did send home.
One way of doing this is like a friend of mine that traveled fore 5 months and did not take laptop with him. He backed the images up on a hard-drive like the Jobo 250GB GIGA Vu Sonic Stand-Alone Data Storage Unit and then he posted the cards home. SDHC cards are cheap nowadays and smaller cards like SanDisk 4GB CompactFlash Memory Card also this is therefore one way of reducing baggage weight and not to costly. What ever method you use backup is vital and so is note taking and writing down informations about places visited
Here are some tips to think about before you lace up your shoes and start the world walk.
1. Plan your trip and write down a list of what you are going to take pictures of before you go. Still be prepared for the unexpected and keep an open eye and mind.
2. Create a keyword set in Lightroom from the list before you go to speed things up
2. Convert images to dng and Back up each day saving the metadata with the images
3 Send backups home if you are staying long on the road
4. Import into lightroom or other software and add basic keywords each day. If you are travellng with out a computer make a list of keywords for what you snapped that day. It will speed things up when you come back home.
5. Write caption first and keywords will follow. If you are taking pictures of official building or historical monuments find the web address for information to add later. Think like a journalist 5W who, what,where,why,when
6. Keep a diary or journal. Even though its just a short one filled with keywords it will help you with final captions. If you are not comfortable with notation on your phone or iPad keep a pen and notebook handy. Its a must have for any travel photographer
7. Take pictures of signs to buildings and tourist information signs so you do not have to go back with overweight of brochures.
8. Track your photowalk. Use your gps or gps system on the camea or some gps app for your smart phone and then add the tracks to metadata.
9 Remember to pack some model agreements if you plan to sell images of people add the informations to the file
10. Find a local contact, fellow photographer or other that can help you with the accuracy of your metadata. Local contact can also be fun to go out with on a photowalk and its good to do it in the start of your trip so as to get to learn the environment and about special places that you can then come back to again for the light you want.
And an extra advise. No matter what, be polite. Smile will get you far and often out of trouble to. If people do not want you to take their picture respect that.