Well the actual conditions (powder, packed powder, etc) would be best determined a few days before your trip. That being said, I have been to Heavenly before, and can offer the following advice:
- It has fantastic glades and is renowned for its tree skiing/boarding. If this is your cup of tea, I would suggest a helmet (I would suggest one anyway for that matter)
- There are numerous cat-walks (long flat roads) that connect the major portions of the resort (Notably the California and Nevada halves of the resort). These are easily traversed by skiier who can skate and pole themselves along but can be very frustrating for the snowboarder. You might consider purchasing some collapsable backpacking ski-poles which telescope down to a portable size and keeping them in a backpack.
- Check your board for nicks and dings before going. Core shots and gouges are generally repairable at any reputable board/ski shop-- or you can buy a p-tex candle and give it a go yourself.
- Buy a snowtool that you can keep on you while boarding. At the beginning of each day check to make sure the misc. screws/bolts are all nice and tight. I also do this daily after lunch pit stops. There is nothing worse than losing a strap on the slopes and having to a) call it quits early b) get down off the mountain c) buy more equipment.
- Powder requires less of an edge then packed surfaces (check the forecast once again). Drag your thumbnail across your edges near the middle of your board. It should 'catch' a bit. I would not reccomend home-sharpening your edges, as they require a subtle bevel that difficult to reproduce without specialized equipment.
- Powder requires more wax to keep a decent head of steam (i.e. powder slows you down.) This can be particularly important in deep snow that does not have much of a pitch...you may find your self hiking out of powder runs that posed no problem the day before when in packed surface.
Technically you can target your wax to the temperature (i.e. you can get waxes with different melting points), but generally speaking an all purpose wax will serve you just fine.