Landscaping forum would probably be the most help. I'm concerned about the end of your walkway, Is it stepping stones on a slant like it looks & not even with the rest? Easy for anyone to fall or trip. Someone could step on far right end of that 1 sticking out & break a foot or hip, Might be better to put another row of stepping stones but they must be very flat & not tippy at all. They can be slanted down to drive if they are not at all slippery when wet. But they must be secure in the dirt as any gaps can cause you or visitor to fall. If you are young you might have baby & packages or friends or grandma come over & most walkways should be at least 30 inches. Narrow walks easier to lose your balance especially is arms are full. They have people that are better at judging what plants & how it would look best but please take care of those stepping stones, you don't want an accident & be laid up!!