Yes, I think your soon-to-be-Goos would LOVE a hammock! Mine love them, and take MANY comfy naps in there. One thing I'm big on is making my own toys. So I've made my own hammocks, tunnels, and other things.
For the hammocks, the first ones I made out of denim from an old pair of jeans. Those last a LONG time, but when they were worn out, I made new ones from scraps of a nice soft, cottony, terry-cloth fabric. These are a BIG hit, and are also lasting a long time.
Degus love to dig, and in nature, create complex tunnel systems for their homes. So if you can provide a digging pit, or at least some tunnels for them to walk through and play in, they'll be quite content! I have made my own tunnels. Some of my tunnels are made out of 3 inch PVC pipe that I got at the local hardware store. I got a really long pipe for pretty cheap, and cut it into the lengths I needed with a jig saw. Some of my other tunnels are made from the empty tube a big roll of linoleum flooring came on. It's like a gigantic paper towel tube. I cut that into the lengths I wanted too.
Several of us buy bird toys for our Goos, as Goos like to climb just like birds do. I have a Booda Rope Bird Toy - it's a bendable rope you can attach anywhere in the cage for your Goo to climb on, and they LOVE it. With bird toys, you're pretty much safe as long as you stick to the wooden toys - don't get the ones with cuddle fish or rawhides on them of course.
If you like making your own toys I have two that I make on a fairly regular basis that are big hits!
One is to take an empty tube from the toilet tissue, and put a couple of tidbits of something tasty in it. Then, stuff both ends with kleenex or papertowels. Your Goos will have to figure out how to get to the tasty tidbits - they love that! Then they'll have nesting material, and a tube to carry around.
The other one is to take a material scrap (maybe from an old sock, or an old t-shirt) and sew it into a pouch. Put a couple tasty tidbits in the pouch, and then sew it completely shut. Your Goos will have to figure out how to get to the tasty tidbit, and will love shredding the material!
Just a few ideas I hope will help you! Everyone else will have good ideas too!