I used a Childish, Creative, Genius sim for the challenge. Childish allowed her to meet her social needs by talking to a stuffed bear. I focused completely on painting to earn money, so Creative helped there. As far as I can tell, Genius didn't do much other than give her a few tense moodlets because she wasn't getting enough of a mental challenge.
She completed the Painting aspiration and then the Mansion Baron aspiration and only maxed out her painting skill, but she completed Mansion Baron on day 20. A lot of her home value was from all of her paintings on the walls ... walls and walls of paintings!
I noticed that sometimes if I moved her paintings to the wall in Live Mode, it didn't count it in the home value (sometimes it did, but not always). So I started moving the paintings from easel to wall in Build/Buy Mode and it added the value consistently every time.
She caught herself on fire while cooking about halfway through. That was scary! She managed to put it out by jumping in the shower, then raced back to the kitchen to extinguish the stove and one counter. I think we were both a little hesitant for her to cook after that.
Fun challenge! I may have to strategize and come up with a way to accomplish it even quicker. ;)