I'm not 100% sure this is what you are after, but you can insert a new number column in a table, and then edit the column so it is a formula... [Project Start]-[Early Start], for example. You didn't say what you have tried... I don't know how much experience you have with making formula fields in Project.

Now that you have the calculated field(s), View the Network Diagram.
Format > Boxes
Copy the Template you want to add the field(s) to (a Copy button is provided) to launch the Data Definition dialog box.
Give the template a name
Towards the bottom of the Data Definition dialog boxin the "Choose Cells" section you
can specify which fields you want to add and where to put them
After the Data Definition dialog box is closed, you will need to use the template drop-down to apply the new template.