Apparently it's not just the house design itself, it's the land layout around the house that's broken and results in sims getting stuck.
I'd also highly suggest tearing down the combined school/stadium and building separate school and stadiums since combined school/stadiums are broken (local football team always loses and it stops your children being able to attend graduation day.) I've made a separate stadium and school using just the base game and expansion flora:
http://www.thesims3.com/assetDetail.html?assetId=8697055
http://www.thesims3.com/assetDetail.html?assetId=8697098
Also you'll need to set the front doors for the Collins and Vidal houses near the park as they aren't set properly. If there's still problems with the Collins house you can create a similar effect on the outside of the house by deleting the walls with the arches and using moveobjects on place 3 ModCol columns where the arches would've been and colourise them using the same pattern/colours on the letterbox.
These and all the other suggestions other people have mentioned won't solve all lag issues (brand new game after brand new install of everything and still jitters like crazy) but should help to make it lag less often.
