One package for each file?
Yes it works.
i have one question in regards to the "Reorganize." section of your post:
I have split the file into two and extended :components keyword paramater in asd file accordingy. Do i have to define a separate package for each file in package.lisp and add the (in-package ...) expression in each file?
Because when i tried to just use the same (in-package ...) as in the first file without defining any additional package i am getting an error when loading the system via quickload, telling me that the package of the second file name does not exist...
In my case it would be enough two have one package for both files.