Bill,
Have had some problems determining exactly what can be achieved with PLANIX
myself. If you are budget driven try 3D Home Architect by Broderbund - There is
a new version believe 3.0 and can be had for around $30 if you search the net.
I've used the 2.0 version and it will do most of the things you are interested
in doing. The 2.0 version could not import .dxf files which caused me to look
at Planix. You can also checkout Designworkshop at
www.artifice.com. These seem
to be the under $100 packages that do the best job.
Good luck