A good way to get some idea of value is to go to Ebay and look at the items "completed listings" price. That way you will see what the item has sold for and what the item's price was that didn't sell. Obviously there is a wide variety in the pricing because condition, desirability and seller's reputation all come into play, as well as timing.
I would expect that a one time buyer, who will purchase everything, will offer significantly less money to buy the whole package than you could get by selling each item on your own, of course this would also require a lot more effort on your part. So you have to decide if it's worth the extra few hundred dollars you may make on the sales to do the homework and selling yourself, or if you just want to dump it all for the quick buck. Only you can make that decision.
I would expect that a one time buyer, who will purchase everything, will offer significantly less money to buy the whole package than you could get by selling each item on your own, of course this would also require a lot more effort on your part. So you have to decide if it's worth the extra few hundred dollars you may make on the sales to do the homework and selling yourself, or if you just want to dump it all for the quick buck. Only you can make that decision.