To access the DeltaNet and TravelNet all that is needed is the 9 digit employee number (retirees keep the same number as they were when active) AND the password.
A little coaching in how to go about using the system and you can make a go it.
Easier if your job function is/was passenger/customer service.
That can take care of the basics of listing and checking space availability.

The only other thing to help with getting a better picture of seat availability is knowing how to do a dummy booking at Delta.com to see the seats available (or not)
on a specific flight.

In a bind there is the fall back method using Delta's Travel Line the 800 number 1-800-325-7123
What you will need to use this method is the employee's 9 digit employee number and the seniority date mm/dd/yy then use the voice automated prompts.
It is slow cumbersome but it works when computer access is not conveniently available !