Red Coach is a classic diner, right down to maroon vinyl booths and swivel-chair counter seating. A Portland institution since 1965, the two-story eatery's convenient location amid chic downtown restaurants makes it a nostalgic enclave for Portlanders craving no-frills fare. The popular Karl's Special ($7.95) pairs a cheeseburger with a heap of crispy crinkle-cut fries and a drink. Thick, sugary milkshakes ($4.50 for a small), available in the standard flavors, are a tasty finishing touch to the golden-brown grilled tuna and cheese with fries ($7.25). (WH)