Hi Neuroticnelly,
This glitch seemed kind of familiar to me. Specially with towns that have shared rabbit holes. So I searched on the problem and found this.
Sim can’t enter Rabbithole
http://sims3.crinrict.com/en/2011/06/bug-sim-cant-enter-rabbithole.htmlIt basically says to either delete the rabbit hole and replace it with a new copy in edit town or change the lot type to another community lot type and then back again.
--- Build/Buy Mode > Community Objects > Building Tab is where you'll find some of the rabbithole buildings.
Click image to see larger view:
Sounds like this has been pretty common for a few years now.
Hope this helps,
MrsFlynn