I would think so, too. Even if she became confused and started walking, most of that area is residential/commercial. The "open space" areas are right along Pleasant Grove - behind the aquatic center and Mahany Park. Then, there are huge open space areas up along Fiddyment Road (near where Pleasant Grove intersects Fiddyment). Other than that, though, mostly residential/commercial - and it seems way too long to not have found her if she was simply "confused" or had a "spell," in my opinion.
I'm really impressed with Vjac's vigilance, though - your mom is very lucky to have you looking so hard, and I know we're all hopeful she returns safely before the birth of her first grandchild!