I have an auto insurance refund check made out to me, and I wish to deposit this into my GMAC Demand Note account which requires having to mail it in. Would the correct endorsement be: For Deposit Only to Demand Note Account #xxx-xxxxxx-xx Then signed by myself and Printing my name under my signature?

Sounds good to me. When sending a check through the mail "For deposit only into..." is the correct way to endorse this prevents someone else from trying to cash/deposit into another account as a third party check.

If you have any further questions or concerns about mailing in your deposits, direct them to your financial institution for specific policies that I may not be aware of.

Anon. You are 100% correct.
And anytime you have a check in hand, and know that it will be deposited, always put that endorsement on it right away, so that if you should lose it, it would not be cashed.

If you bank has online banking, you could deposit it into your bank account and have your bank send a check to the other institution. That way you do not have to worry about the mail delivery. With my bank, I know exactly when my money will arrive at the other institution.