I made this bag for my friend (for >40 yrs now). She has multiple sclerosis and uses a walker. The pattern is Simplicity 2300, bag A. I modified the pattern just a bit so there is no seams on the side and the zipper pocket in the front has a bias finish along the top edge which was sewn down rather than another seam there.
I also added a button closure and a key keeper (hook on a strap so the keys don’t get lost in the bottom). The shoulder strap (not well seen in the photo) is adjustable.
I think it really needs to be a smaller by about 25% as I am concerned that if it is actually full it will be too heavy and make it too difficult for my friend to lift the walker when needed or make the walker unstable. She hasn’t had the bag long so no reported problems (so hopefully my worries are unfounded).