Dan,
I found this software to be helpful. (As you say, to evaluate various options... not to replace the engineer.) The UI is very straightforward and the evaluation version is free. The limitation of the evaluation version is that the nodes (or members?) are limited to something like 20 or 30 elements. If your truss is symmetric, using the proper constraints, you could effectively model a truss with twice the number of nodes.
http://www.engilab.com/beam2d_ml.htm Thomas
