We are driving the Kenai peninsula in an RV and plan to drive the Anchorage to Seward route and then the Seward to Homer route before having to be back in Anchorage to return the RV--which route has the more spectacular scenery and more things to see and do (not interested in tours or excursions...just seeing the sights!!!)

They are both very beautiful. You will find almost anywhere you go in that part of Alaska, the scenery is beautiful. Try to stop at Portage Glacier and, if you able to walk fairly well, make sure to visit Exit Glacier. This Glacier is a fairly easy 1/2 mile walk to a spectacular glacier.
(It's a walk, not a climb).
I hope in Seward you will plan to take a day cruise. These range from 2.5 hours to 8+ hours. They are well worth it. I wouldn't miss the opportunity.
In Seward, you can also go to the SeaLife Center. Although small, it's really great.
Homer is wonderful, especially the little shops and restaurants along the Homer Spit. You can even take a fishing excursion from there.
Have a wonderful trip. You'll love it.

Those routes are both very scenic, and very different. If you take only one, you'll miss out.

The very best part of the drive on the Seward Hwy is going to be from Anchorage along the Turnagain Arm. Heading south from Anchorage the highway is going to divide. Seward is on one side of the mountains, Homer on the other. Both towns are very beautiful but maybe the overlook just before you get to Homer is more spectacular than just before Seward. We didn't think the road between the split off, thru Soldotna and almost to Homer was spectacular although there's some nice views of the volcanos across the bay. It's quite possible to take most of the day to get from Anchorage to Seward if you stop for photos, visit Portage glacier visitors center, etc. but without stopping it's about a 3 hour drive. Homer back to Anchorage will be about 5 hours. You'll want to plan your lunch stop ahead of time. Ideal from Seward to Homer might be lunch in Seward, dinner in Homer. We had a hard time finding the seafood place in/near Clam Gulch or Nilnilchik. It's on the water, very casual, and you can't see it from the highway. Very easy to miss. This is an area where the Milepost is highly recommended.

On your drive to Homer, be sure to stop in Ninilchik and see the old Russian church. It is very scenic!

Keep in mind that this is a very small town, so you may not know exactly where it is, particularly since it is off the main highway and there are no signs to help you find it. However, if you stop at any business establishment, they could probably tell you how to find it. We stopped at a general store where they had picture postcards of the Russian church for sale. We merely took one of the cards to the counter and asked how to find it.

If you want to eat between Seward and Homer (but it's much closer to Seward), I recommend the dining room at the Kenai Princess Lodge in Cooper Landing. Or, Gwin's in Cooper Landing. It's been a few years but I think both are still open.

I agree they are both scenic in their own way. When you go to Seward, go see Exit glacier. Then after go down to the waterfront near the sealife center there is an RV parking lot there( not the one where you park and stay, that is near the harbor) The view on a clear day is beautiful.
In Homer, well its also beautiful, go see the spit, there is also RV parking. On the way there there are lots of little pull offs to see the volcanos in the distance along with the mountains. Those little Russian towns looked interesting, I would have gone if I had the time.
Hope that helps

You didn't say when you are making the trip. If it's anytime soon, be sure and check on road closures. They are having fires right now and those could close roads on short notice.

I think the wildfires are dying down or have ended but we had the largest wildfire in the nation in Ninilchik (right outside of Homer) in the past couple of weeks. I haven't been down there since so haven't seen the damage except on television. Both Seward and Homer are nice seaside communities with different personalities. Homer is on a long narrow "spit" with campers and RV's on both sides, quaint tourist shops, and small restaurants. Homer is sorta "hippy chic". Seward is geared more to the large cruise ship passengers and day time cruises. Also a fun place. Any drive in the summer in Alaska can be beautiful as long as you don't mind long road trips. Watch for moose - they are all over the place. Have a great time!