Second Job need advice

So I currently work in hamilton, ontario as a psych rpn and just recently got a fulltime job on a different unit than I originally started in the hospital on. I work 12 hour shifts, max 7 shifts in a pay (ofcourse less if I have stats, drop days or vacation).
my fiance and I are getting married in two years and with him in school its currently really difficult to start saving. So I have opted for getting a second job. Currently I have an interview booked for monday (only 4 hours after coming off nights) but it is in cambridge (about 40 mins away). Its part-time and I believe they are 12 hour shifts, but I'm not sure how part-time it is, or if its casual (although I did state directly in my coverletter about my availability)
I was just wondering if I could get some advice from any nurses working 2 jobs. How difficult do you find it? Do you commute a fair distance and what is that like for you, especially when you get home? I don't want to get burnt out, but I would love to have my foot in two doors at once so to speak.
We're driving to cambridge sunday afternoon to see what the drive is like, amount of gas used, etc to see if it would be something i would consider.
Any information, tips etc you could give would be great! thanks!!