There are several places that will rent you a 152/172 around ANC. I am biased towards Take Flight Alaska since I learned to fly there, good operation, largest rental fleet in AK but its all 152/172 and I think they might still have a 172RG and a Duchess. They are based at Merrill Field. Wasn't inexpensive to rent but then where is. Phone number is (907)274-9943. Depending on the weather the flight to Seward is very scenic, and only about 45 minutes each way I think. Also you could fly to Girdwood and walk to the Bake Shop, great sourdough pancakes. Double Musky is also not out of walking distance if you are looking for something more filling...