Level 38 seems to be the key to unlocking chapter 7 - also had about 90000 points. The latest App upgrade may have helped because my neighbors have gone from 17 to nearly 200 in a day. I'm also getting challenges- never received these until the combo of chap7 and the new release. However, now I can only use 10 energy power-ups each day, and energy takes 4 mins to grow instead of 2. My biggest tip, use the levels up to 38 to gain as much wealth and as many points as possible!
However, it could be that the latest upgrade was what added Chapter 7. Evidently when the Facebook version first came out, a new level was added every week. So who knows what may be the plan for the iPad version.
Come visit my garden- playID is same as my username here. Happy landscaping!