There is the Tony Knowles that can be either walked or biked. 11 miles from 2nd Ave to Kincaid Park. But I would never be there without a car- so much more to see. Upper Turnagain Arm- south, north to Eagle River Eklutna, even around Anchorage- Flat Top hiking, Alaska Native Heritage Center, botanical gardens- etc. go to www.anchorage.net and request a visitor guide.
If the weather permits, rent a bike downtown near Blondies. Biking the Tony Knowles trail around the airport is fantastic. There are lots of wildlife including moose. Plan for at least a 4 hour roundtrip, but its well worth it.
Also, a good resturant is the Glacier Brewhouse. Reasonably priced, for Alaska, great service and excellent seafood. Simon and Seaforts has incredible crab legs, best ever tasted, great view, but very pricey. Both are downtown. For early morning coffee and breakfast, Country Kitchen is open 24 hours. Downtown also.
Furthermore, try to catch the Spirit of Alaska IMAX at the Performing Arts Center. A great way to relax after the bike ride.
Finally, souvenir shopping in Anchorage is cheap (relatively). Buy about 40 postcards (10 for $0.88 at Polar Bear Outlet, same cards are as high as $0.25 each in Skagway) and send them out at each port of call. We did all of our Christmas shopping in Anchorage before the cruise/tour, and sent everyone cards from each port. (Hint - Bring pre-printed address labels with you from home.)