How old is your computer's harddrive? I had this same thing happen to me a few months ago,it took about an hour to load the game,and another half hour to load each lot,I had Seasons so I also had constant crashing and BSOD(especially in my downtown area)I found out my problems were caused by a bad harddrive,it finally gave out in January,after I got my new one installed I reinstalled everything, I added Bon Voyage,and I have had no trouble at all,the BSOD went away,even when my downloads folder was up to 8 gigs,it still only took 15 minutes to load the game with the new one installed,however,I recently had to delete my downloads folder due to massive file corruption,and even with all EP's up to Bon Voyage my game now takes about 1 minute to load(I use only Maxis recolors now,and custom clothes and hair)I have a suspicion that your problems are caused by a bad harddrive,or too much CC
One other thing most people forget is to defrag thier hard drives.... this is very very important as you store more and more and more and more CC :-P
Also I've read a couple of other threads that have helped me. I used a utility called the compressor to compress my CC and went from 3.5 Gigs to 2.3 GB (I backed up all my CC just in case first) and that seemed to help me quite a bit, also i made all my CC read only, that helped even more. Don't ask me why... I read it, decided to give it a try and it helped. Lastly i got rid of my cache files and let the game rebuild them and with those three things i was able to notice a real difference. If you decide to try it please, please, please don't forget to backup your CC :smt120