My approach I write direct to excel, open a excel file and fill in 1st dwg block details. When you open next dwg get last cell address and then fill in details, keep repeating.
The write to a csv may be easier the only difference is to use "A" not "W" when you open file this will append to an existing file.
I would look into accoreconsole to process a lot of dwg's else just a script open a dwg, run a lisp, then close.