Each one is different but both are beautiful and not to be missed - as long as you planned to go to one. Just do some Google searchs to get an idea. There are many sites to give you ideas.
We stayed on the Homer Spit. We also were walking in town and were admiring the hanging flower baskets. A woman noticed and started a conversation about the lovely flowers. She invited us up on the ridge overlooking the waters to her home for lunch and to see her flower and vegetable gardens. What an interesting experience! Her husband cooked us a just-caught halibut lunch sandwich - he loves fishing and she supplied a salad from her garden. We spent a few hours with them listening to their stories of living there.
This is what Seward has to offer. We loved it, also.
We took a glacier cruise out of Seward and also out of Valdez to Columbia Glacier. Be sure to get the 2/1 Coupon book online before your trip. It will save you a lot of money and there are many things in it to use all along your trip.
Unless you like crowds don't go the July 4 weekend. The locals love to take trips there.
On your way down from Anchorage be sure to stop at Portage Glacier - we stayed at Williwaw national forest campground right there.
.... wish we were going back!