what do you do after recruiting mew in pokemon mystery dungeon?

Answer 1

nothing

getting mew is actually not a storyline requirement - but it does get rid of the word "go" next to "buried relic"

there are many other places you can go, instead

getting mew does nothing for the storyline, or gameline quests

Answer 2

http://www.serebii.net/mysteriousdungeon/legendary.shtml -You can catch the other legendaries.