Hi Bazotto. Giving away too much too early is an odd concept, and difficult to define, since people come onto the site for help. And people have the choice not to come onto the site until they've completed the puzzle. But that's just a general observation. In this case, the thread has been dead for over 2 days, so I think there shouldn't be any difficulty discussing your questions openly.
You're right about 3 letters changing in column 4, becoming O, R, D. I didn't consider that the other 2 replacement letters would be E,R. That's certainly a logical assumption, but turning to the east after the 'D' of crossword, a 4-letter word associated with 'crossword' can be created by changing 2 letters to R, D.
And I also like your idea that 'check' might follow 'cross', but that is a digression. Which reminds me, the NHL season is about to begin...which is also a digression.