Thoughts on this;
Why wasn't the leaking valve found during the dealership PDI, or yours?
By leaking valve are we talking about the ball valve?
With a week old trailer the approval of this repair should be open and shut. Dealer submits to Keystone, Keystone should approve same day unless it is more than described, parts should be on hand and repaired next day....JMO.
In the situation you describe I have to believe that the dealer is the problem. Nothing about a toilet valve takes anything more than a couple of hours to fix. Approval, on a week old trailer is foregone. Parts should be on hand for something so common; if not, a 2 day deal to get them. Again, your dealer is the problem IMO.
I would be doing a face to face with the service manager and/or the GM or owner of the dealership on a daily basis.....but that's what I do and I'm retired
Note on the backup mentioned above. You have a week old trailer that should have been delivered without problems; especially the one you describe. There should be no wait-you move to the front of the line-it's a new trailer they failed to deliver in an operable condition.