Before doing anything, I'd take it to a local automotive upholstery shop. A friend was selling his 2010 Dodge pickup, but the driver's seat bolster was ripped bad and foam was missing. He was about to spend 6 or 7 hundred to replace the cover and foam. I insisted he try the upholstery shop because they can work serious magic. They fixed the foam and patched the bolster for around $150. It's worth having it looked at and quoted.
2004 National Seabreeze LX (8321) Workhorse W-22
Towing: 2010 Subaru Impreza