Question's about PD nursing

I have an interview with the hospital this week for a PD position. I just passed my Nclex-pn and this would be my first interview. I have to say this wasn't my intent when I put in my app, I was hoping for a floor position on med/sug. I have read over some of the posts and kind of have a sense what this job intails but I'll find out more this week. Anyhow, I was just wondering what are the most important things to consider when deciding about the job's benifts and expenses. Should I expect milage? If so,what is a good rate? Is the pay lower then floor nursing? The one thing I do know is that it is a per diem positon. I guess it is good since I can pick my own hours and be on call becasue im still in school and plan on gettign my RN but other then that i'm clueless about per diem. Any and all input would be helpfull. Thanks!