infimurf, that is one magnificent build! I'll bet it's enormous, too. Are you donating it to a museum when you're done, or are you adding an extra wing on your house for it?
Here are a couple of pictures which are similar to the ones I used when I started (and never finished) pricing out my 1/48th Mercury Redstone launch diorama which I never built:
http://www.mostlyclassics.net/images/mercuryredstonelaunch.jpg
http://www.mostlyclassics.net/images/mercuryatpad.jpg
I had priced out about half the Plastruct needed to make just the launch tower (the red and gray structure) and was up around $150.00 when I quit pricing. This was maybe 15 years ago. In today's prices, my guess is raw materials for the launch tower, the yellow cherry-picker, and the base with its tracks and other stuff, would put me back around $750.00.
And, as you can see, the Mercury Redstone launch complex was much simpler than the Shuttle's. And much smaller, too, even taking into account 1/48th versus 1/144th scale.
If your heart is set on building the Shuttle launch pad and tower in 1/144th, grit your teeth and shell out the $175.00 for the Revell model. Then be prepared to do lots of accurizing. But the Revell model, even for $175.00, is a screaming steal!