If you have 6 months to prepare, that's lots of time to prepare.

Simply ride often and make it several times per wk. Try to extend your distance at least on weekends. Yes, try good times to drink water, eat some food, etc. Same for clothing for different conditions. Stay safe, alert, etc.

Above all: Don't overthink this to prepare for this. Just get onto the bike and ride to enjoy as part of your training as you ride longer/abit faster.

Really....don't overthink it. Otherwise the mental barriers will be the biggest barrier of all for you.