Yeah, the Murano definitely falls more toward the car side of a crossover than a 4x4 side (like the liberty or something). It
does have 4wd (technically all-wheel drive, which is slightly different), and handles snow and stuff quite well. It's handled some muddy bumpy fields at my parents' farm quite well (on the way to landscape shootings). At $32K though, I try to avoid any serious off-roading.
As for the continuously variable transmission, most cars are built like bicycles--a couple of sets of gears that change at various speeds to give you more torque (oompf) or more speed. The CVT has cone-shaped areas with a belt between them (instead of meshing gears), so there's no jump between one gear and the next, just a smooth transition. You don't go from first to second to third, but rather an infinite range of higher and lower torque.