Hi M.,
I breastfed both of my kids for a long time. I took a 1 night, 1 day trip when my son was 14 months. He was fine when we returned. I was nursing him mainly at naptime and bedtime. Later, after my daughter was born we took a 3 day, 2 night trip. She was 8 1/2 months. I pumped alot before hand so my mil had enough milk for her. At that time she was getting a fruit or a veggie in the afternoon with her cereal. I pumped while we were gone. I had an electric Medela. It worked out well. I was pumping about every 3-4 hours.
We we returned, she was ready to nurse. She didn't have a problem at all. You could have the sitter feed her from a sippy cup if you are worried about the bottle nipple. Or even just a regular cup. Yes, they can drink out of a regular small cup! (When my son was 12 hours old the nurse made me give my son 2oz of formula because he hadn't urinated yet. She gave it to him out of a cup...so it does work. If he had been my 2nd i would have told the nurse to get out!)
If you decide to take him with you breastfeeding will work great. We've taken many trips when the kids were babies. You can pull over anywhere and nurse them.
Have a great time on your vacation. It is always good for Mommy to get recharged!
L.