I think its very much about diet. I can tell when one of the cats has helped themselves to something they shouldn't have and licked a bowl clean (pheweee! stinky poo!)
After trail and error for a few years, we now have perfected a system -
Diet - good quality dry food, with a bit of raw meat now and then
Water - changed daily to keep them drinking lots of clean water
Tray - hooded tray (it has one of those carbon filters but I think they do nothing at all and I don't bother to change it anymore)
Litter - Breeder's choice paper pellets
#2 Cleaning - empty pooper twice a day (sometimes three, once when we get home and once before we go to bed, and good stirring to airate and soak up and spread out wet litter)
Total cleaning - whole lot gets emptied to compost down, then sprayed out with bleach spray and wiped out once or twice a week
Litter tracking - we have a carpet mat in front of the tray that catches most - but if its tracking a lot it means its time to change it cos the pieces are getting small enough for the cats feet to pick them up!
And get the dishes in the dish washer before any chance of a pre-wash cycle (a la cat tongue) ha ha ha
Plus the whole lot is in the laundry, with a cat flap to the rest of the house, so there is no smell at all.
Good luck!