I was hoping to hear from somebody who may have dealt with this situation since my experience with financial institutions is that they can make things very difficult, which is of course good in some ways but awful in others. Regardless, I contacted treasurydirect.gov and they wrote the following:
If you are not named in the registration of the bonds as the trustee, or if there are co-trustees named in the registration of the bonds and one of the co-trustees is deceased, the trust agreement will be needed to verify that you are the currently acting trustee. If anybody named in the registration of the bonds is deceased, a certified copy of the death certificate is also required.
The Special Form Of Request For Payment Of United States Savings And Retirement Securities Where Use Of A Detached Request Is Authorized (FS Form 1522) is a request for payment form. If FS Form 1522 has been properly completed, signed, and signature(s) certified, the back of each bond does not need to be signed to request payment. The properly completed and signed form is in lieu of signing the back of each and every bond.
The FS Form 1522 is available at: http://www.treasurydirect.gov/forms/sav1522.pdf
Send the entire transaction (bonds, form, evidence) to this office:
Treasury Retail Securities Site
PO Box 214
Minneapolis, MN 55480-0214