Further to above comment about Recreation Centers, I love doing the No Skills No Problem scenario, giving myself different challenges as to how quickly I can reach the goal and what sort of character I use.
Because it requires so much of the Sims time, I tend to use a Loner character, Freegan and Green Fiend. Then I Use the broken Community Lot feature to my advantage. Precisely because no one comes to the lots anymore, my penniless character can move in. I've even managed to avoid all interactions with other Sims using this, which again allow them to concentrate on what they're doing.
By making them join the Scientist career, I do that until they get the SimRay with Transform object upgrade, then they Quit.
Using the SimRay I can transform all the rubbish piles in the original Community Lots (soreading them out first. If you're lucky, you'll get a bed and a hydroponic or plain planter.
I don't use the build menu to do anything except knock out walls and move existing furnishings to start with. My aim is to see if I can build a Recreation center as well as reaching the Scenario goal. If you make it a Landfill lot, the resulting dropped broken objects can be transformed.
Diving for ingredients will give you plants. Dumpster Diving, finishing Collector Aspiration and planting things like Money Tree will help.
I allow my Sim to bring bought camping objects onto the lot and sometimes transforming them will help fill in gaps in required furnishings.
You'll end up with top range showers and refrigerators.
No fires from transformations.
I've even got pianos from Transforming objects.
To complete Recreation Center, the only things I've always had to but is the Jungle Gym and pieces of Exercise equipment. The photo above is one run through.
Will be interested in Feedback if anyone else tries to do this.
26-30 days to finish scenario seems to be the average.