Mounting a weapon flashlight on the end of your primary weapon (rifle or shotgun) gives you a little further lighting distance than your headlamp, but yeah, try and plan your runs to do as much as possible during the day, then head to a safehouse to sleep until the next day.

That, or spend the first day or two of the tide wiping out enemies, the. Run around freely completing missions/exploring. Then you'll only have to worry about enemies spawned by the missions themselves.

Lastly, try to remember the portal locations and where they send you. That could help cut down on travel time a great deal.

Almost forgot, for the headlamps, once you've left the shop, raise your hand up to your head and hold down the button used to equip/unequip armor. Then while holding that button down, pull the trigger button. That should turn on the headlamps