Women's usual "problem area" unlike men's is the lower stomach especially after having children. So that is the area to target. Back problems are an added consideration too. Try doing knee raises laying on your back and bringing your bent knees up to your sternum . This will take pressure of the back unlike straight legs. Also if affordable I found an AB ROLLER to actually work well without the neck and back pressure you mentioned. (believe it or not!) 1 of these "gimmicks" that actually works.
Also, do a form of cardio to assist in burning your stomach fat since that is what really does the work and not just "spot reduction". Even walking more is good. Along with healthy eating choices (lower fat). You can strengthen abs with muscle training yes but only with the combination above will the abs be visible without the layer of fat.