Try calling KEH etc. saying that you would like to sell them the equipment. They will probably quote you a price 40 -50% less than they will sell it for. That would give you an idea with some wiggle room as to what to ask for the equipment.
Whenever I want to sell something and have no real idea of its value, I simply list it on eBay with a $1 starting price and let the market decide. I've never been disappointed with the results - especially when the item was a camera. In fact, I do this even when I do have a pretty good idea of an item's value.