It is doable. If it is a budget job maybe this would be acceptable. The right thing to do, labor wise not a whole lot different, would be to rewire. At this time you could split up circuits, bring things to code, and replace the old wire. Running a ground wire to each box would be a pain in the rump. Trying to fish a single wire into an already occupied box with wires already coming through the knockouts....I would pass.
The customer wants to keep the cost down so I will probably leave the 2 wire recepts since its not against code on an exhisting home, and just add a GFI circuit for the bathrooms and kitchen and change the main panel. There is a sub panel (fuses) which I can just splice the circuits and them run back to the main panel and have all circuits at one location.
The Golden Rule - "The man with the gold makes the rule"