Check your local Corps District office for contol monument manuals. Also you should be able to get that infor from your state DOT. Most Styate DOT's produce a state map showing general elevations.Then there's alway the software from Maptech and DeLorme that let you view quads and pick off Lat/Long. Also USGS quads are a good source. The 15 minute quads are pretty accurate. You can scale the lat/longs off them.
By the by, there's an upgrade to the Corps "Corpscon" software. It's free. Type "corpscon" into your browser. Great program for converting lat/long to state plane and converting between the 29 and 83/88 systems. Give scale factors and all the other data you need.
Here's the corpscon link:
http://crunch.tec.army.mil/software/corpscon/corpscon.html