Our cat could care less what's in his box when he has to go.
We use Slide (Arm and Hammer?) litter. Cleans up easier and doesn't seem to track as much as some of the others we've tried. It's a bit spendy.
We also put pieces of carpets/foor mats near the box "entrance" to try to get him to shed the litter on his feet before he gets too far from the box, which is near the side entry door.
Makes cleaning it up easier. When we stop for rest/food/whatever, I shake the carpet pieces outside while DW does a quick sweep out the side door of the broader litter box area. Quick and painless.