AVENEL, N.J. On a busy stretch of Route 35 near Rahway, N.J., one of the nation’s last Kmart stores looks like a relic from the past. Its big red K is faded and cracked. Inside this most American of retail stores, popular for K Cafe luncheonettes and Bluelight Specials, a sign promotes 60 percent off clothing. A dining-room table was on clearance for $89, while Route 66 jeans went for $10.99 and pink ladies’ neck sweaters for $12.49.