You got 'possums?

You know, those big rather scruffy looking creatures with a long naked tail that look like a rat from a nightmare. Well I got possums and I really wish I didn't.
I am not sure when they arrived but some months back I saw this tiny gray creature in the backyard, in daylight mind you, foraging among the plants. On looking closer I saw it was a baby possum. No sign of Mom anywhere and I thought she must have got hit by a car or something. That was then! Now, I think it was just a ruse to make me feel sorry for her kids so she didn't have to feed them! Of course I felt sorry for the little 'orphan' at the time, so I set out a bit of dog food for it, well at least that was until I realized it was helping itself to the cats food, and all the cats were complaining long and loud because their food dishes were empty.
I tried putting the cat’s food down in the daytime, thinking, in my foolish way, that as the possum got bigger it would be nocturnal. Oh no such luck. This possum obviously does not know the meaning of the word, because I have caught him strutting the backyard at all hours. Not only that, but Momma has decided they are onto a good thing and she has been coming out to feast also. They have outfitted themselves with a cozy nest at the back of my garden shed. I know where they are, sleeping in the very back corner and emerging to have a quick snack and then dodging back underneath to warmth and safety. OK I know I should get to the back of the shed and remove them, bodily if need be, but you have no idea what is in my shed. It would take the combined efforts of three men and a strong boy to get it all out! Even then, as the shed is about on its last legs, they would for sure be back in through one of the holes, once I had all the junk, er I mean stuff, replaced.
Tonight I went out to check the cat food and I thought it odd that the cats did not come out of their bed, which is on a table in front of the shed. THEN, I realized that the 'cat' had a naked tail - yep, it was the back end of the possum, curled up with its fat butt in the entrance of the cat’s bed and chomping on the food in there. I shook the bed and Momma just stuck her head in the back corner and ignored me. Finally I had to resort to low dealings and I tipped the whole table until she fell or rather rolled out onto the ground. Did she run? Did she heck! She shoved her head into the honeysuckle bush and ignored me. I figured she was working on the assumption that 'if I can't see you, you can't see me'. Short of removing her bodily I had no choice but to leave her there. I am hoping that she goes off in the spring and finds a mate, preferably in the next county.