I didn't expect to finish the challenge this early, but I just kept on playing and playing because it was so much fun. I ended up with:
94 nooboos
Looking forward to hearing the strategies afterward. Wow, 183!
Having played Sims 1, 2, 3, and now 4, it's really lovely to discover new parts of the game in the course of doing these challenges (I'd never spent much time in San Myshuno, just one example.). Thank you all so much for giving me something positive and fun to do.