The South Ro LDoN entrance appears to be in sro_2_obj.s3d, so if you have that in your Live directory, copy it over to your Underfoot directory.
The list of missing files in Underfoot is maintained here:
http://www.eqemulator.net/wiki/wikka...ssingFilesList
If there is a missing entrance in North Ro, it is likely to be in nro_obj2.s3d or one of the other nro s3d files in that list.
The old commons zones would be commons*s3d and ecommons*s3d, but I don't see any missing files listed for either of those two zones in the current list.