I love Riding Link's Boomerang with a Peach Bomber. XD
Anyway, my two cents is that the matchup is close to 55:45 favor por Peach. Link has a sword, so it force's Peach in a more defensive standing. But Link's Projectiles are a bit problematic for camping and defensive play, especially when Peach's projectiles are thrown items like Link's Bombs. Fortunately, Peach can glidetoss, which Link only has item boost, so there's some silver lining there.
Watch spacing, which I think is the most important thing when facing a Link because you need to stay somewhere were you won't be pelleted by projectiles, yet close enough so that you do fall prey to his sword attacks. I think playing Ivysaur really helps since Ivysaur's range against most opponents seem to be at the kind of range which Peach should be to Link.
Off stage, it's not too difficult to edgegaurd him. I don't really try to gimp Link with Fair since Link's sword is quicker than most believe, so either do a Bair, or come from the top during a jump. Try to footstool him or come down with a Dair since Link has very little option if he's trying to get back on stage and the opponent is coming at him since his Uair is so long that he can't necessarily risk the attack lest he might die from the fall.