Whenever we have gone away, we would take lots of bottles already washed up, then we took either our cold water steriliser (when he was on a few feeds a day) and some milton tablets, then would sterilise before going out, as the milton water is sterile for 24 hours. Then it's just a case of taking the bottle out when you need it, and using a ready made carton with gaviscon (our DS has/had reflux too). You don't have to leave the bottles in the milton water to be sterile, you can seal the bottles and then they are sterile for 24 hours.
Once our wee man was only on 2 feeds a day we just took our travel steriliser which takes 1 bottle. You can also get travel steriliser bags