Man the corners were more of a pain than they should be. I used a 1/4" round over bit for my previous boxes, but wanted a bigger roundover on this one. So I got a 1/2" bit, but it didnt fit inside the plastic faceplate of my router.
I couldnt find a replacement faceplate, so I just took it off and did as good as I could without it. It wasnt nearly as easy or pretty as it could have been.
The corners were with the router too, just flipped the box and rounded them after doing the legnths. Then I sanded them to make it look better. Much sanding involved to get the shape I wanted. Thats a good thing about working with MDF though, very easy to manipulate through sanding.