I found DS Investigations very troublesome to use as a teacher, because there didn't seem to be enough opportunity for pencil and paper practice. I don't really like "drill and kill", but there should be at least a little bit of it. There were pages like this with Investigations that you could use, but it was really left up to the teacher to decide whether or not to print them out.

A teacher who really knew what she was doing could make Investigations works in a fabulous way. A teacher who didn't know what she was doing, could really bomb with it.

Singapore would be a really good choice to help augment a program like Investigations at home.