Estate planning question

You should have some options in a town as big as Chicago.  There's a Chicago Audio Society - sure to be several people with the same questions as you.  As mentioned already, there are also many audio stores in the area, several featuring used equipment.  Have you checked Saturday Audio Exchange or Chicago Audio?  

figure out what you want first:

• easy process
• good home
• highest price
• please the family

You can't have all 4. They are kind of conflicting goals.

I think expecting 25% is realistic because the dealer will drop the price to 50% of the value and will keep half of the proceeds. 1/6 is pure greed.

Being in the business for for well over 30 years I have seen this scenario several times. I would personally recommend contacting all the high end dealers within 50 miles or so from your house and have them come over to inspect all the gear. Let them make a cash offer or sell on consignment. Then have them pack and move the gear out with a complete list. The gear is then out of your space and you have the cash, or you get payments as the gear sells off. It's better to work with a local dealer, especially if you have purchased from that dealer. 

OP might want to investigate the Saturday Audio Exchange on Belmont in West Town.  People there might have a recommendation for him

My wife knows exactly what my stereo costs and intends to keep it if I croak first. Our death instructions when we are both gone is for the executor of our estate keep the stereo for their own use or sell it and keep the money. The executor knows what it’s worth. I also included resources for them to find fair value and how to sell the items, and the name of my trusted audio salesman.  I chose the executor poorly if they cannot figure out how to sell it for an appropriate price.