Travelling for Excelsior Grads

I would think that the agency that is placing you for travel assignments would be the best source of immediate info regarding your qualifications to take any particular assignment in any particular state. They are responsible for sending somebody that can meet the needs of their client institution. If you can't work somewhere because you graduated from Excelsior and your nrsg license won't endorse into a particular state, then the agency logically won't try to send you there.

Illinois is one of the states that makes it difficult for Excelsior grads, the following is directly form the IL Application for Endorsement:

NOTE: Excelsior College a/k/a/ the University of the State of New York Regents External Degree Program is an unapproved nursing education program in the State of Illinois due to the fact that it does not have concurrent theory and clinical components as required by the Illinois Nursing and Advanced Practical Nursing Act. Therefore, it is considered to be a correspondence course which is identified by the Act as not meeting the requirements for licensure.
There is a provision in the Act to allow for individual review of applications from applicants who are graduates of such programs provided the applicant is
currently licensed in another U.S. jurisdiction and has been actively practicing
in clinical nursing for a minimum of two (2) years. The applicant must have an
employer complete a VE (Verification of Employment) form verifying two full
years of clinical practice as a registered nurse. This must be submitted with the endorsement application. When the application is complete, it is reviewed by the Board of Nursing for a determination of eligibility to be rendered.