"You can then section the solid at whatever intervals you want. The end faces will then give you the bulkheads with all the longeron notches. "

You cant do this in Solidworks because it doesnt recognize cross sections in the model building area as "measurable" geometry. BUT, you can just create your model, however you want, and then create a drawing of it.

In the drawing view, simply create lines where you want your section views to be, then make them section lines. The software will automatically create the section view off of which you can then dimension whatever you want.

Thats the easiest method. Sorry for my rambling.

What is Key Creator? Ive never heard of it.