Rhino,,,, WOW you have brought back some memories for me!
I grew up in Fulton county and lived in Macomb for a few years in the early 1980’s. I have ridden bikes over both the bridges you have posted from over there. The one just north of Bernoditte was the main way in and out of town back then. Did lots of riding and exploring Camp Ellis. The target emplacements were right along rifle road. Some of the buildings were still standing.
If you get back over that way I have also crossed the bridge that is north west of Bernoditte on what google maps is calling North Tarters Ferry Ln. It may not still be there, is was in bad shape and the road even worse 25 years ago!
Another steel bridge was in London Mills right in town I have herd that it is still there but only open to foot traffic now.
Back then there use to also be a ferry still running crossing the Mississippi, some of us would make
day rides over and cross on the ferry and come back at Keokuk.
If I can think so some other bridges up that way I will point you to them. I have not been up there in over 20 years though.
Thanks for the memories !
Checking here http://en.wikipedia.org/wiki/London_Mills_Bridge