Just to show that there is only a personal way to deal with this and NO general process or panacea ...
I rarely get dehydrated and just drink normally. I have a low tolerance of alcohol and get tipsy very easily BUT find that alcohol has much less effect on me at altitude and can drink much more than usual.
I leave my watch on departure time until I land and then alter to arrival. If on holiday, I sleep when my body wants to. If working, I drive on through and try to arrange meetings in some sensible fashion. Sometimes it's easy and sometimes not.
