Get a cheap Chinese light https://www.amazon.com/dp/B00F9UZABA/ , run it on lowest setting with a fat external battery: https://www.amazon.com/gp/product/B00AAQOV5E/ I've gotten 10+ hours out of similar combo with older light.
I just got this to ride (bike) some trails at night, cheap and it works. The battery it comes with is not great but it is a lot of lumen/$. I bought an extra higher capacity battery, use that as primary and the one it came with as backup.
EDIT: The head strap that came with mine is very small, but you can take the plastic part and put it on another strap/mount to helmet.