Salary negotiations: how should I go about this?

Hopefully you gave them the two week notice. This happened to me. I did stay on for an additional month and tried to train someone. It was hard enough in person. I can't imagine trying to do it remotely. It sounds like you're in a no win situation...if you don't they will perhaps not give you a glowing recommendation, and if you do and the new person just doesn't get it, they won't give you a glowing recommendation. Can you stay an additional two weeks? They pay your hotel bill, expenses and keep you on salary? If so offer that. I wouldn't agree to the remote training scenario. It won't be successful, in addition to having to argue about wages.