Northern Iowa, Previously Colorado. Havnt put sand in the back since high school. I also now run Studded winter tires. Winter tires help the most when you actually really need it - stopping and turning. All 4wd does it help you get moving and possibly not get stuck - obviously offroad/trail/deeper snow.
In fact - my wifes last 2 cars I purposely bought front wheel drive instead of AWD and just put snow tires on. It's cheaper, better gas milage, less maintence and is actually more effective than AWD with regular all seasons.
If you dont want to shell out $2K for a winter tire set, just roll in 2wd until you need it, it's a turn of the dial for 4WD. I run 2wd 99% of the time. the 1% is in an active snow storm/blizzard before plows. After plows - 2wd is enough with winter tires even in a RWD truck with no weight in back.