Welcome, @Scott1710! Good luck! This challenge is the only thing that kept me playing this game for so long!
@SnazzyTazzy, that is sort of up to you. You will not get the 5 points for doing only part of an aspiration level, but there is no reason not to do them if you still wanted to. If you are trying to complete the goal in the quickest time possible I would recommend skipping them, but if you are playing they way you want to, do anything you want! ^_^
One thing I really recommend to both of you: if you have the house set up so that you can still get to your mailbox outside, keep a close eye on your Sim. The mailman stands by the fence for a really long time after throwing your mail over, and I caught my Sim several times trying to go talk to them on their own.