Re: ...beer and wine available on the bus....
Alcohol is a diuretic. https://my.clevelandclinic.org/health/diseases_conditions/hic_avoiding_dehydration
Alcoholic and caffeinated beverages, such as coffee, teas, and colas,
are not recommended for optimal hydration.
I'm partial to Hammer Nutrition products, Heed for short events, Perpetuem for distance events. While individual serving packets are more expensive than bulk containers, they are convenient for travel and easy to tuck in baggage spaces.
But that said, if you are just walking around, water or watered down de-fizzed Coke should be fine for rehydration unless you have as fussy stomach.
If you just want electrolytes and don't need calories, try Hammer Endurolytes and water:
Endurolytes comes in convenient capsules or powder form. You can
swallow the capsules hourly, or open them and mix your own amount into
your water bottle, whichever is most convenient for you. When you
don't feel like taking capsules, Endurolytes Powder is the answer.
Sodium (as Sodium Chloride) 80mg 4% Chloride (as Sodium
Chloride) 120mg 4% Calcium (as Chelate) 100mg 10% Magnesium (as
Chelate) 50mg 12% Potassium (as Chelate) 50mg 1% Vitamin B-6 (as
Pyridoxine HCL) 13.2mg 660% Manganese (as Chelate) 3.2mg 160%
L-Tyrosine 100mg † Ginger Root 10mg