I agree with Remy - this would make a really great annual.

Tricky.

I don't suppose there are any vehicle plans that are definitely in the public domain that you could trace?

Or if you had a model that you could photograph from above, you could trace the photo without worrying about copyright.

All this wonderful creativity! :D

Similarly, if you want 2.5 foot wide walls you will need to edit the 5ft snap grid (right click the Snap button to do this) and make 4 snap points instead of 2, then draw your room 1.75 ft larger than you want it on the first snap point outside the boundary of the floor space.

Or for 2 ft wide walls you need to use the 5 snap 5 ft grid.

I think you've done a pretty good job :)