1.  I would ensure that EVERY UPDATE, INSERT, DELETE query inside the Access database has "Use Transaction" property = FALSE/NO.  This will DRAMATICALLY INCREASE the size of your DB if TRUE/YES.

As far as doing this via DTS I would NOT recommend it.  You don't know if someone has left the application open in which case you will NOT be able to and could possibly corrupt it.

Instead, how about adding a button or an ON database CLOSE event to COMPACT/REPAIR ?