How can I disable the Print Range | Pages options in GoView.PrintShowDialog() ?

I think this will help:

The problem is not to override what the user enters, the issue is to disable page range selection in the dialog when the option is not availableā€¦

GoView.PrintShowDialog() uses a Windows.Forms.PageSetupDialog, which does not allow disabling the sheet range controls.

Using a Windows.Forms.PrintDialog lets you do this by setting AllowSomePages to false (and it has a bunch more options).

Do you see any reason not to use PrintDialog instead of PageSetupDialog ?

PrintShowDialog uses PrintDialogā€¦ but the control you have is through the PrintDocument pd parameter if you call base.PrintShowDialog.
Sure, you can completely override PrintShowDialog and set up PrintDialog the way you want. just return the result of the dlg.ShowDialog().