@chadwixk 

I would create an inventory adjustment and write everything off to zero, and use a "Income from liquidation of inventory" income account, or sub account to "Income from Sale of Business". Then use that same account as the credit in the journal entry where you record the liquidation, for the actual amount you sold the inventory for

"How do you account for the good will aspect? "

Goodwill is an account that is used by a buyer of a business not a seller.  The excess paid over book value is simply profit on your P&L

"How do I account for remaining payments (all principle, no interest) the buyer is to pay over the course of a year?"

Create a journal entry: debit "Receivable from buyer of business", credit "Income from Sale of Business"

The above assumes you file tax on accrual basis.  If cash basis, use an Invoice rather