As for having a good locking folder, the KaBar Dozier you selected looks like it would be a very good knife.  A 
Spyderco Delica would be another good knife to consider, roughly the same weight as the Dozier but with better steel imo, AUS-8A vs VG-10 and that Delica is flat ground.  There are so many... 
Either would be good to drop in your pocket, but for just opening boxes and cutting cardboard, a folder with disposable/replaceable blades is my preference.  Ive got the Husky shown above.  
Edit:  Just noted the price point - $21.38 on Amazon; that makes the Dozier very compelling.  Still, $7.88 for the Husky at HD with 10 replacement blades.