It's almost impossible to sell a complete pre-owned system. Practically speaking, the only way to do it, is to sell the package at an 80 or 90% discount to a wholesaler.
You will get a better overall number and move things far more quickly by parting it out on eBay or Audiogon. Used equipment buyers want the specific component that they want, not entire systems. And, unless you relish doing this for months and months, you must be prepared to ship things, even overseas.
If it all sounds like to much trouble - and, make no mistake, it is work - PM me and I will suggest a wholesaler.