Well, it depends. On some environments such as Lucas Arts they used Unix based OSes to develop SCUMM. With grep and such, editing and porting the engine could have been a breeze.
Half joking, by the time of the NES port he would have certainly had many available options for all that , but even with access to a timesharing system with real storage and all that in the earlier 80s having at least sections on paper for easy reference against printed manuals was handy.
