For multi-day stuff I use an Oregon. Can load it with whatever maps you prefer, uses AA batteries (rechargeable or not), big screen. Upto the 700 series now but you should be able to find older models as well.
I’ve had 20hrs out of one charge, that’s with a lot of the energy saving tricks and not looking at it every five minutes – easy up in Scotland where you set off on a track and it’s three hours before you come to a junction.
The Etrex models are also popular (and a bit lighter since they don’t have the recharging circuitry built-in like the Oregon).