We did it quite a bit when ours were babies and it was a once a day procedure. But before I go on let me say that we never heated a baby's bottle in our lives! All bottles given to our lot were at room temp and it was the best advice we ever got. They never complained! And we never had all that hassle of heating and cooling bottles. Our procedure was adopted on the advice of a good friend who was also a GP and mother. But each to their own and all that.
So we would bring the steriliser with us and simply wash and sterilise the bottles as normal. Then it depended on if we were making up a feed or using ready mades. Ready mades are very handy but a bit expensive.
Procedure for ready mades:
Set up bottle empty after sterilisation and just leave it as until you need it. At feed time, open and fill with ready made and job is done! Very, very handy process.
Procedure for making up feed:
After sterilisation fill bottle with boiling water. Close and allow to cool to room temp. Let it sit there until you need it. When you need it add in the feed, shake and serve. Almost as handy as a ready made. We used to have a container (designed by the maker of the feed) that would hold 3 pre-measures of dry feed. Then all you had to do was tip and it in.
Simple - no fridge, no bottle heater, no checking the temperature of the feed etc.
We did this home or away. Three kids and all got the same treatment. But if your baby is already used to a warm feed they may not take the feed at room temp.
As I said this is what we did but it is not exactly the same as what is recommended by the makers of the feed. Decided for yourself.
\\ps the others beat me to it. As you can see we were not alone!