Okay here is the latest...I have put plaster of paris over my great stuff and foam. Hope that is not a chemistry experiment gone bad 
See attached pictures...my questions.
1. What is difference between plaster of paris and sculptamold? I used PP because that is what I had.
2. Do i need to apply the PP to the riverbed or will the WS water go straight on my MDF board base?
3. My plan is to do the first coat of paint or so on the bench then move the 2X2 piece to the train table. From there i will do the final detailing in place. I think I can envision it better there also.....I plan to make this like a puzzle so I will not finish the edges and put my next piece (built primarily on the bench) put it on the table then do the edges of both pieces once on the table for conformity. Does that make sense?
So with what you see I think next is to sand a bit then paint. Does anyone have "go to" colors for the river?
Thanks again, and I am open to any comments or suggestions...
