I have always thought about making something like that and I would love to give it a try sometime. But I don't have a need too.
One thing that you must be aware of:
1) The largest area in cubic Feet is 1640. Anything larger will require a second part.
How big is the plant and office space combined?
What kind of plant is it?
Do you have conveyor systems or is it all just molding machines placed on the floor?
????
Since I don't know what kind of plant it is I don't know if it is feasible or not. If it has a conveyor system in it. It would be harder to model that quickly, unless your just looking for basic shapes. Then with basic shapes it could probably be done fairly quickly. But I don't know what you do so it's hard to say.
I'm sure most people here and most other NG would suggest some other CAD software. But I enjoy pushing SW to it's limits. I do it everyday. Finding new ways to get a job done. I enjoy a good challenge, and doing a plant layout would definitely be in that category.
So for you to decide to do it in SW:
1) Know your overall size of the entire plant?
2) Know your limitations?
3) What would be involved to make it look the way you want it?
4) Are you willing to accept a large challenge such as this or are you looking for the easy way out?
5) Plan it out before you make your first part!! Because down the road your going to have issues come up and you don't want to spend all your time trying to figure it out along with planning your next move.
I think I am just rambling now! LOL
One last thing though, you might want to ask this question at comp.cad.solidworks NG. I believe there are some people that has made chairs and stuff like that. That you may be able to use in your design.
Hope that helps, Scott Baugh, CSWP

George Koch Sons,LLC
Evansville, IN 47714
sjb@kochllc.com