I'd say wait for a sale, but definitely get the pack. If you are a roleplayer, you'll love the military salute that comes with the career, marching around, the option to bug sims and later listen in on them... all of that works in every world. Sparring is a bit of a letdown, because there is no winner, the sims just spar and then shake hands.
While you wait for Strangerville to drop in price, check the gallery for a navy base that you can make into a dorm for your cadet to be, so that he can get his degree in style in Annapolis. I don't remember the lot names, but I think I saw two and also some coast patrol ships.