No, the fact that you were to fly overseas would not affect negatively on your resume, depending where and what you fly, it would actually help you stand out, particularly if you fly Etops, obviously you would have international experience, bigger airplane possibly (fleet commonality with other airlines here in US)? All that would help.

I've asked this question numerous times to recruiters from several major airlines and lccs, they have all seen the added experience as a positive. You manage to stand out compared to all other pilots who have been flying regional jets only.

I have several friends who have received calls from legacies while being overseas.

Now, the logistics to come back, accommodate job fairs, accommodate interviews and such, yes that can be a challenge, but that's a different story.