Turn off WAAS/EGNOS. That's about a 20% battery hit, and you don't need the extra accuracy it gives.
The backlight isn't too bad - at full backlight 100% of the time it would still be only about 100% battery hit - at 40% light say 10% of the time its almost negligible.
Battery Save mode extends life by about 30%, no more, OTOH it doesn't affect performance much either.
Hybrid-type battery cells are pointless unless you are unable to recharge immediately before the trip. The break-even point is around 5-6 days - if you can't recharge within 6 days of your trip, use hybrids - otherwise, no point.
Always match the cell type in the menus (Alkaline, NiMH etc) to what is actually fitted.