Danny, my area has loads of deer and rabbits but my special homebrew recipe seems to keep them at a distance. Human urine dabbled around the garden perimeter after each rain. I save it up during the winter and spread once plants have germinated, not too close to the plants but close enough. It's free and plentiful but it does go fast during a rainy season. Might go into business one day, label the product as "P1ssoff!" ;o) - Try it, they won't like it! (esp after a long winter, ha). Note : not sure if it will deter possums - they smell so bad themselves that they may not notice.

Bird netting wrapped around the sides should keep cats out, and is probably about as cheap as visqueen, although I haven't really checked. Use vinyl coated chicken wire to keep squirrels and other chewers out. It's more expensive than visqueen or bird netting, but squirrels etc. will chew right through both of them. This is five year-old vinyl coated chicken wire I use to keep squirrels, as well as birds and cats out:

I don't have any advice, but mine has also always stayed in the back of my property. Now I'm worried. (From what I hear, death is the only sure cure.)

Coll, I think your garden is just stunning! You mention the garden is fairly small, and you have about 125 hostas, and also that you have a bathroom area for your dogs. How big is your yard and garden, actually? I posted some photos of some of my hostas the other day, and am going to add a couple of wider angle photos to show how the yard sits (size, arrangement, etc). Would you maybe be able to do the same? I'd love to see the total overall effect. You said that in the photos you put up, we just couldn't see the weeds, failures, etc, and I have to admit that I tried to avoid those in my first photos as well, but I'm going to go for it and lay the whole thing out there for all to see! LOL! I'm hoping you'll do the same :-)