Look at the designation on the cord's outer jacket. If you look up the designation you'll find it's rated for outdoor use/exposure and should not be a problem leaving it exposed. I have our 30 amp shore power cord plugged in 365 days a year, either at a CG or at home. It's still in excellent condition 8 years later except for fading.
Physical protection is a different matter tho. Is this 30 or 50 amps? Shore power cords are not rated or permitted for underground use or inside a raceway (ie., pipe). Although not strictly allowable per code, using PVC pipe like 3" *should* work, depending if it's just on a lawn or under a roadway. Underground conduit is normally required to be at a depth of 2' or so depending on soil conditions and location.
If it were me, I'd use some conduit + wire or direct buried UF cable. Install a receptacle near your RV and a weatherproof junction box next to the power source/pedestal and convert to a properly rated extension cord their.