I know this is a year old, but another vote for proper infrastructure grade cable. That means it should be rated for direct burial, shielded, grease-filled and rodent proof. The cost of cable is usually outweighed by the cost of proper burial and terminations, so don't skimp on pairs, sooner or later you'll always need more. 12 should be considered minimum, and if you're holding speed events or GS with multiple start and interval locations, 25 pair on at least the lower portion of the course. Best scenario is if can get the resort to partner with you on placement of the cable. Most resorts have excavators that can do the work, and they may well be reluctant to allow a third party operator on the hill in any case. If the race club buys the cable, hopefully the mountain will provide a machine to lay it. Add some volunteer labour (keeps those young athletes fit in the off season) and you will have the line buried where it's needed and maybe, just maybe, the ops or snowmaking guys won't damage it, because they know it's there.
Proper terminations and distribution are also needed, or you waste your cable money. Fred has posted pictures on the site of his fibreglass station terminal boxes; most Canadian posters will know of Steve Mullen's exceptional work that extends from small club ski areas right up to World Cup and Olympic venues. Either way, it's critical to protect that cable and provide terminations that won't be degraded by weather exposure. Anything above ground should be in conduit right to the box.
Yes, this stuff costs money and isn't sexy like that new timer or display setup. But in the long term, you get your money back in the form of reliability and longevity. Volunteer hours are precious, don't waste them on doing the same job over and over because you cheaped out.