So I I have a 55 gallon tank and I need help decorating

So I have a really big tank (55 gallons) and it opens at the top(I know!) And I don't want to give them a bad set up. She has three hids(one fake wood on cold side, one real wood on warm side, and one plastic humidity hide).Substrate isn't deep,deep but enough to dig, and it's coco fiber, topsoil and sand, she has a lot of fake long flower plants that cover the warm side and the cold side(there is green yarn ball that is tangled in the plant and I can't get it out),and a big piece of real wood in the middle. The old owners painted the back of the tank a bright blue and I don't know how to get rid of it without hours of pain, I have a heater and temperature and humidity gauge. What do I need to improve? And anything I need to take away