Thanks for all of your replies. That is exactly why I posted here- I know that you will all understand how I feel.
The clutter is not such a big deal. I can put things away in closets and I do not fear the dumpster. lol.
The main problem is cat odor. It seems to have permeated my home- because even with the litterboxes clean, there is still a strong odor. Part of the problem is that I can't smell it, myself, so I had a friend come over and give me his honest opinion and he reported that yes, it smells like a litter box in here- even with clean cat boxes. I suspect that there may be some place that one of my furry friends is "cheating," but I haven't located such a spot yet.
I bought some clumping litter (I have been using clay) so that I will be able to remove the urine more effeciently, instead of it sitting at the bottom of the box for days. This was my landlord's suggestion ,and I think it will help.
I also purchased a Febreeze air purifier for the area around the litter boxes, and also Febreeze super-strength spray for the area around the litter boxes and also to freshen up the curtains, sofa, etc.
I will be renting a rug doctor carpet cleaner next week, to get the carpets and furniture extra clean. I will use the extra-strength pet odor remover with that. I also have pet odor enzyme spray which I can use if needed.
OK, so beyond those things- does anyone else have any good strategies for removing and controlling litterbox odor?