Thanks for looking up this census record...it's hard to identify Reeder for certain. The age in 1860 record you found it about right, so could be him.
I also found a record in St. Louis, Mo, 1870:
RAEDER, Frederick W. 38 architect b. Prussia
Harriett W. 25 MASS
James A. 1 Mo

Again, no idea that this is the right Reeder.
Have had no luck finding any kind of pension record for either Reeder or widow/minor.

It looks like after he transferred from Missouri to the Adjutant Generals Office in Washington, he then transferred to the Invalid Corps. So we'll be looking for something further there. Though I don't think it will shed any light on his activities in Missouri. But it would be nice to know where he eventually ended up, and when he died.

Thanks Again!
Cynthia