[steve_and_pigs]

For both cardboard and coroplast, zip ties work well. Punch holes in your material and zip tie things together. You can probably use the sides of the cage as something to tie to in addition to the ramp and second level.

Fleece can be cut to any shape with scissors. Cover the ramp and second level with some fleece. You can get some small baby fleece blankets at places like walgreens for $1 or two. Wash it weekly.

Use plain cardboard. He will probably chew it some, but he most likely he won't eat it like candy.

If your cage is small, you need to let the little guy out every day to exercise. There is probably no room for him to run laps. At that age they usually like to run dash-like sprints in a circle or a figure 8.

coroplast can be found at sign and plastic stores. Grids for making a c&c cages and play pens can be found at target.