Did you try to remove all your downloads to see if without any the game would run normally? If it does then add small batch at a time to find the culprit(s).
You can package sims using SimPe, follow the step 1 of this tutorial to do so:
http://www.insimenator.org/showthread.php?t=18184As for your lots, the ones that are in the lot bin can be saved by backing up your lotcatalog folder.
I do not know how to package lots that are place in the hoods from outside the game.