Thanks for the tips/suggestions guys. I've been looking at pics of old wherehouses for ideas and also downloaded some building instructions from the Lego site itself to give me ideas.

I plan on doing a bit of a moc up/test build, to try some of the different build styles, out of stuff I have already. Hopefully that should give me an idea of what works & what doesn't, along with I need more of.

As for colours, I think I'll worry about that last. I was thinking orginally of the red brick with grey brick edging & trim but I'm seeing a lot of stuff in sandstone, so I might have to think about the Tan colour Lint mentioned.
I have a few Daily Bugle sets that I got on clearance, that I can use as a colour guide I guess? I'm pretty sure that uses Tan bricks.

Do most building mostly use the 1x bricks now or still the 2x bricks?