I wouldn't use anything scented, because rats are so sensitive.
I don't like Carefresh personally because it does nothing for odor. Poop falls right through, so the litter boxes smell horrible no matter how much I wash them, and it's impossible to remove poop from the boxes without a complete change of litter. It's very light, so the rats push it right out of the boxes and it gets everywhere. Luckily the stuff I've used isn't dusty, but some people have problems with that. Also, some people have had their rats get mites from Carefresh, which fortunately has not happened to me.
well as far as not liking carefresh....they claim there product is low on dust....yea well let me tell you...it very dusty! I also found the odor control to be very poor. And i was using the "ultra" carefresh. I remember one instance that i had changed the bedding and did a normal clean up of the cage. By the 2nd day I came home from work and was like...omg that smell. This is mainly the reason for the switch over to News. I find that using the yesterdays news is just better in all aspects of bedding/litter.
My rat isnt litter box trained but seams to prefer a certain area or corner.
Once hes a little bigger, and once my $$ funds are a little bigger I'll invest in a larger cage...something with multiple levels this way he doesnt have to always be walking throught the bedding...he can hangout wherever he likes.