With DS1 I had real difficulties establishing feeding, including mastitis so bad I was back in hospital when he was 7 days old. Due to that, he had some formula and knew how to use a bottle from very early on.
However, I knew that I was going to be living in a tent for 4 weeks (turned out we got a caravan, but still), then travelling longhaul for 4 weeks, when he was 4-6 months old. I REALLY didn't want to sort out formula and bottles and sterilising and right temperature water through all that.
Added to that was, all the hype about BF, my own stubborn nature that doesn't want to change my mind about stuff, and the cost of formula, and I stuck it out.
I went back to work part time when he was 3 months old (DH and I had alternate days at home with him), and worked full time a couple of weeks when he was 4 months old, and again full time work when he was 7-11 months old.
I had a Medela Symphony pump hired from the hospital for the first block of working, and used a Medela hand pump for the second. DH would sms me each time he fed him, and let me know how much he ate. I would then go to the rest room (bed for those feeling ill, not loo) and pump out the same amount. I put the milk in storage bags into the work freezer, and took it home with me in a little cool bag each night.
DS1 was exclusively BF till weaning, and had his last feed at 13 months old. I stopped because we were TTC.
DS2 is 5 months old and EBF. Again I had pain for ages at the start, but I knew it got better with DS1, so I stuck it out, and now it's fine. I will be home with him until he's almost 1 this time.
I think the feasibility of BF and working must depend a bit on the logistics. Is there somewhere that you can pump without feeling really vulnerable? Can you store the milk? It sounds like you'll have a lot of really long days, so that will mean a lot of pumping. It's doable, but will take commitment from you.
If it is inconvenient, uncomfortable or even impossible for you to pump, mixed feeding is always a possibility, though you'll have to see for yourself at the time how your supply goes.
Good luck! There's loads of good advice here about how it's impossible to tell when kids are older (or even tiny!) what they're fed. Loving caring parents who research what's needed to feed a child safely (BF or formula) are the most important.