No, the response should be that Romney has decided he doesn't have to do comedy. He pays his aides top dollar so they can tell his jokes.
As for the Seamus episode, there's no point in telling reporters about how crowded the family station wagon was or about the shield Romney assembled to protect the Irish setter from the wind. Or that dogs traveling on passenger planes probably experience a similar amount of stress.
If he had it to do over, Romney should say, he would have hired a car and driver for his dog. The public would get that.