Not difficult at all, just involves some waiting due to the infamous slowness of the CA BRN.
You have two options after graduating from Roseman: apply for the NV BON first then endorse your license to CA, or apply directly to the CA BRN. Most of the people in my class did the former; I did the latter. I should also point out that you can physically take the NCLEX anywhere in the country, it doesn't matter where, as long as you've directed your application to one state's specific board.
A quick overview of my timeline (2016):
Sometime in February (I forget when, sorry) - Did LiveScan fingerprinting in CA, sent transcripts from my other schools
February 24 - Submitted my application to the California BRN online and paid. Everything is complete in my application except for my Roseman transcripts as I hadn't passed the ATI comp predictor/graduated yet
March 2 - Registered for the NCLEX online and paid
March 11 - Passed comp predictor, officially graduated
March 18 - Transcripts mailed out to the CA BRN from RUHS
June 9 - Received my ATT in email (finally!)
June 10 - Took NCLEX
June 14 - Officially an RN! (my name & license number showed up on BreEZe that morning)