Hi
I travel regularly to Australia and I find sticking to the same time of day works for me - at home i apply after my morning shower so I do the same there. I do try and use a bit of oesteogen during my journey, now that I use Lenzetto I just do two sprays roughly half way through my journey, when i was using gel I did a couple of pumps. Not a full dose but slightly more than half, just to keep topped up. I have a Mirena now so dont have to think about progesterone but when I was taking utrogestan I simply waited until my first evening there to take it (again following same time of day as at home) as I figured that missing one dose wasn't going to hurt!
I'm not hypersensitive to changes so it works for me.
I also make sure I carry my HRT in hand luggage so there is no risk of losing it if bags for awol! I take a copy of my latest prescription and also collapse down the boxes of each medication and put in the bottom of my hand bag. I've never been asked for them but I like to have them with me just in case

Have a wonderful holiday and enjoy your celebrations
Suzie