my main advice would be to watch out for anything that could bring on sciatica. i had torn spinal ligaments in 2010 which resulted in the alignment of my spine being slightly off. no big thing, no pain, no issues (the misalignment i mean, not the spinal tear, that shit hurt like anything).
this January, i was knocked over by a skier and landed flat on my tailbone, causing bruising. the pain didn't go away, and a few weeks later, i caught an edge and went down pretty hard. i had a lot of stiffness in my lower back after that for about 24 hours, until my leg just clamped up. i couldn't stand on it, sitting or lying down made no difference, the pain was unbelievable. I was out of work sick for 2 weeks and am still feeling the effects.
basically, keep up the core strength stuff, watch for any tweaks, twinges or stiffness in the area, and try to keep as supple as possible. and don't let any skiers run into you