First sentence: "I took some time off to travel."

If they ask for details, then list all the places you went, and then if they're curious about any individual one give them more details about what you did there. If they don't ask for any details about travel, then they don't care, and you're not wasting time with irrelevant information by going into detail on travel from the beginning.

It's a risk. If a hiring company searches in your butthole for gaps in employment you're likely better off not working there anyway. There are plenty of other companies who won't do that...