Walton County is very lucky to have a large number of Coastal Dune Lakes in SoWal. You'll find many along 30A. Public access is possible in a number of ways. Look on another tread here today about the new public dock going in at Lake Powell. Eastern Lake has a public boat launch and a small park just right for launching kayaks and small boats (no bathroom facilities, fyi). I see many people taking their kayaks down the public access points that are close to many of the lakes and then launching their boat from the beach into the outfall and thus access to the entire lake.
Walking or biking, many good view spots are along the bike path. Deer Lake has a viewing area. There is a large public parking lot between Seaside and WaterColor on the north side of 30A. You could park and then ride your bike or walk in either direction (from the public parking lot -- turn right or west and Western Lake is very close, if you turn left or East, Eastern Lake will be a nice 4 mile bike ride). Public Parking area between Seaside and WaterColor has nice bathrooms that are at least open in daylight hours.
From East to West --
Lake Powell is between Walton and Bay Counties. It is the largest.
Camp Creek. Those at WaterSound have access to Camp Creek. Others might need to update on other current access for public.
Deer Lake. State Park. Ride or walk along bike path on 30A or along beach. Great viewing area.
Eastern Lake is near Lakewood and 30A (Old Florida Fish House is on Eastern Lake -- open in evening for food, etc.). Small public park and access (corner of Lakewood and Lakeview Drive). There is also a public beach access on the west side of Eastern Lake. Turn on Gulf Drive. Limited parking, but there is more public right of way around than most want to admit.
Western Lake is between Seaside, WaterColor and Grayton Beach. Those staying at WaterColor have an on-site boathouse. Nearby refreshment establishments in Seaside, WaterColor and along 30A.
I think you can go to Google Earth and put in Coastal Dune Lakes, Walton County and see most of the named lakes, about 15 depending on who is counting. Walton County has about 26 miles of beach that is graced by these Coastal Dune Lakes. So, you should have plenty of opportunities for great pictures. The style and choice is up to you.
See video on title page to SoWal.
That should get you started. Got to go catch sunset!!