Deklitch - what worked for me in the past when I got a town to load, but the sims didn't arrive, was to switch households momentarily - DO NOT do this without Metro or Rica's permission, but Twallan has said that a lot of the time this bug is related to the opportunity system and switching household essentially reboots that. On the downside, it will cancel all promised wishes and possibly reset some lifetime wish and skill challenge counters, but traveling will reset some skill challenge counters all on its own...