I find keywording to be a continuous battle to avoid duplicating keywords with synonyms and subtle spelling differences. This is not too bad at home on my desktop computer, where I am using the same library and keywords, but it can get tricky away from home on a different computer. The solution is to add your current keywords to the copy of lightroom you will be using while traveling. Here are the steps to follow:
In the master catalog on your home computer while in the library module execute the menu "Metadata > Export keywords...". This will save a text file with all your keywords. I usually save the file on a USB thumb drive.
Next open lightroom on your travel computer and create a new catalog. The new catalog will not have any keywords in the library. While in the library module in the menu select "Metadata > Import keywords..." and open the keyword file you saved on the thumb drive. Now you will have the same keywords on both computers.
When you get back home export your travel catalog to a USB drive. Attach the USB drive to your home computer and in the master lightroom catalog on your home computer import the travel catalog (File > Import from another catalog...). If you created any new keywords while traveling they will be integrated back into the keyword list on your master catalog.