I've held clearances at various levels for over 30 years. As others have said, absolutely do not leave out any foreign trips. Your list will be long, but look on the bright side -- you'll only have to do this once. You'll have the list in your computer ready for updating every five years. I would do it in a MS Word file and include it as an attachment.

When you have your subject interview, that's the time to explain all your foreign travel and the reason for most of your trips. Unfortunately, some trips taken by some fairly notorious spies resemble MRs -- recurring trips to the same city (Mexico City and Geneva come to mind) for short periods of time. Be completely forthcoming and honest and the worst they can say is "No."

After you get your clearance, follow all the foreign travel rules to the letter. If it costs you a MR or two, that's the price of getting your clearance along with greater job security and a highly marketable addition to your resume.