I am sure people are sick of me talking about it but...I bought 2 mattresses from a gal who makes them with layers and waterproof bottom. They are awesome and very well made. They have saved me a TON on money and made cleaning the cage so much easier. Let me know if you are interested and I can give you her link.
When I started using fleece I had 2 layers of mattress pads under it. This did not work well at all for me because the pads stayed soaking wet all the time and smelled. I now layer fleece, towel, mattress pad, and it works well. I also sewed small pads for the wettest areas made of fleece, 2 layers of towel, fleece. I change the pads out every 1-2 days and clean the entire cage once per week.
I started my fleece yesterday. So far it has been working out well and the pigs seem to like it. I decided on two mattress pads and a few towels because the mattress pad that I had were just a little smaller than the cage. Thanks everyone for all of the help.