Unless something has changed...

I use version 11.04.004. Frankly, I don't use the wizard, but I pulled it up to test your premise.

When the screen for setting room width came up, defaulting to 20', I changed the value to 60', making sure to include the " ' ".  Then I clicked the check mark to confirm that the input value was what I want.  It accepted the value  Then I clicked on one of the side walls. Went up to the value box and input 30'. Clicked the accept check mark. It was accepted. Then clicked on next. Took me to the next set of screens and showed a 30' x 60' room on a slightly larger grid.

So unless the creator changed something, which doesn't happen very often, I believe it does work. But the steps aren't always apparent.

Then again, I'm just an amateur at it. Here's an example of one town layout with grain elevator I experimented with. BTW, the creator of the S/W didn't really think people would do each wall as 3D objects, and he sort of discourages it.

File --> Settings?

Dear Mead,

From a quick Search of the V12 Manual, Page 121 suggests that there is a difference between the 

Dimensions of the Drawing
(See "File --> Settings"?)

and

The "Room" drawing layer.

It seems intuitively logical that if the "Overall Dimensions" of the drawing default to 20' x 20',
then the "Room" dimensions can't exceed that?

Just thinking out loud...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

Room Size vs Drawing size

The wizard allows you to set up the wall dimensions of the room. It then sets up a drawing size based on a slightly larger dimension for the drawing, which is different from the "room".  The settings tab, subsection "units", allows you to define (among other things) the dimensions of the drawing if you need a larger drawing for some reason. I do a lot of drawings where I want additional space for experimentation and still have the grid available. The "grids" subsection allows you to set the size of the major and minor grid lines, plus their color. 

If a person uses the wizard and wants the drawing (not the room components) to be larger, they can use the settings tab. If a person wants to make the room larger or smaller, after having created it with the wizard, they can then select individual walls and then go to the property bar and edit the length of the wall, and then repeat for the other ones, plus having to select and reposition the walls to meet each other.

@Meadmaker - Try

File

Thanks. That lead me right.

Your advice made me go back and focus on each step one at a time.  No assumptions.  That did it.

Turned out putting a space between xx' xx" in the drop tab was the problem.  No spaces, no problem.  It worked fine. xx'xx".  Seemed odd, but hey! that's what it wanted.

Thanks much,  that was getting a bit frustrating.  It's always the little stuff!!

I thought your rendering looked good.  Thanks for the 3D tip.

Right now I'm just noodling out a basic track plan for both On30 and O-scale.  Mainline freight, 1 passenger line in O-scale.  Ancillary small industries that feed into the mainline in On30 with small villages focusing on 1 or 2 bits of interest on each On30 piece (module/lobe/??).  

Figured by mixing the 2, I could do more with the space than all O-scale.

Much appreciated.