Uttarkashi to Gangotri:
Gangotri is 100 km from Uttarkashi , In between Uttarkashi to Gangotri a beautiful small village Harsil is situated which literally means Hari-Shilla.
From Gangotri, Gomukh is 18 km trek.
In between two points where you can get snacks first is Chidwasa and second is Bhojwasa.
Gangotri to Chidwasa: 9 km
Chidwasa to Bhojwasa: 5 km
Bhojwasa to Gomukh: 4 km
After reaching Bhojwasa you can stay at Lal baba ashram for rs 150 per day, which includes dinner and morning tea or you can camp here. Best option is stay at ashram.
Here GMVN guest house is available. In Police station at Bhojwasa you can get medicines in case of emergency best practice is always keep important medicines, first aid box and glucose with yourself.