If you're not happy to make them 4' wide, you'll have to create some internal paths within that space but with different dimensions. The paths would just be on the earth and you could, of course, dig them up each year so as to 'move' them.
I had a number of beds that were 3 or 4 yards along one side, by 2 or 3 yards in the other direction. I would suggest that you don't have them too long - or you WILL get frustrated at having a long walk around when you want to get to the other side!