Dan Drezner and Dan Larison have been going back and forth and back about Mitt Romney's announced plan to take a prestige-building foreign trip this summer. Both of them agree on a few things: Romney has been an embarrassing hack on foreign affairs so far; foreign policy isn't apt to be a plus for Republicans this year, presumably whatever Romney does; and anyway, the election won't turn on foreign policy and national security. It's a good discussion.
I'll add a couple of things. It's not likely that Romney's trip will have any effect at all on what foreign policy specialists think about him. For that, he would need to actually outline policies that impress them -- which is unlikely, since there's a very small overlap of foreign policy ideas that conservative orthodoxy would allow and what's generally popular, and my guess is that whatever fits into that very small corner is some sort of mindless demagoguery that would leave policy specialists not pleased at all. However, it certainly could impress nonspecialist reporters and pundits -- at least enough to keep them from talking about foreign policy as an important weakness of the challenger. If it does that, it's a reasonable use of time.
Which gets to the second point: opportunity costs. What he gives up for a foreign trip are some campaign appearances. But we're talking late July here; I think it's highly unlikely that a couple dozen campaign appearances several months have any effect at all. Sure, if he has nothing better to do, he might as well campaign in front of voters; it's not as if there's apt to be much harm in it, and so why not? But if there's anything actually worthwhile to do with his time, losing stump minutes isn't a reason to avoid it.
The only significant reason I can really think of that a foreign trip could be a campaign error would be the possibility of an effect on the candidate's health and stamina going forward. Don't forget, we're talking about a 65 year old candidate, and even much younger politicians have had minor health difficulties keeping up with the demands of the campaign trail (I'm thinking of Nixon in 1960, who had an ill-timed cold or flu or something like that, and Clinton in 1992, who repeatedly lost his voice). I assume Romney will travel in much more luxurious conditions than Nixon did in 1960, but still, it's a factor to consider.
Other than that, however, I'd say it's a reasonable choice.