For the structure gurus out there:

I recently completed the assembly of a Rix rural timber overpass.  I plan to give it a creosote finish with a fairly heavy weathering to the roadway deck.  My plan is to airbrush the base coat on the entire bridge structure, then go back with various washes and dry brushing to weather and add color to the bridge.  Here's the manufacturer's photo of the structure:

I initially thought that I would prepare a layout as modules based loosely on the railroad where I grew up.  I had started to compile a decent amount of information and purchased a few structure kits and pieces of rolling stock to model.  I even assembled a 'module' to start with.  Then work got stressful and I wasn't even sure I'd still have a job at one point.  The fear of being penny-less forced me to curtail my hobby spending and start putting money aside.  Eventually things got better at work.  I even got a promotion.

While I wait for some sheet cork to continue laying the yard tracks and other areas of the smelter, it was time to mock up some additional smelter buildings and see how they might work in the space.  This is the first area of the layout with any significant structures.  I hope to capture the “industrial menace” of the smelter, although the menace part of the equation may have to wait until it is more than just plain cardboard.

I'm planning a research and rock gathering trip in a few weeks and was going to take a few tubs home.  Are there any tips or tricks for this type of reconnaissance?  Best lines to use when the state trooper asks what you're doing with a shovel on the side of the road?  Are we looking for the finest stuff, or should we be taking larger rocks with the intent to put them in a blender later on?

Thanks!

Rob