IMO, adding sand isn't that bad a deal before the cycle. I've never had a "bad experience' doing that. Sand is usually the first thing i add. But that aside, I agree with the rock comments. Even "cured" rock will have some die off occur. The only way to really avoid that is buying fully cured live rock that's been in a tank running the whole time, and then going straight to your tank with very little out of water time. Heck, I run to the LFS 10 miles up the street, buy some "cured" live rock and it'll still spike a small amount of ammonia/nitrite. Now don't confuse uncured rock with "dead" rock. Dead rock is usually 100% dry, no life whatsoever on it. uncured rock can still have plenty of bacteria and other critter colonized on it, but still the die off will need to be dealt with appropriately. rock will go uncured relatively quickly after being removed from water, but for it to be totally dead, that'll take a little longer. And FWIW, using dry rock, often sold as base rock for the lesser porosity of it, but you can find pieces just as good as live rock and it'll not have the dieoff occur, just will take time to colonize with bacteria but ultimately, works just as good.
If you have no livestock in the tank as of yet (assumption based on your intial statements) don'tw orry bout dieoff or the rock having to travel 3 days or so. It's not going to do anything other than help cycle the tank quicker. You just don't want to add "uncured" rock to a stocked tank with livestock that could potentially be harmed by a sudden increase in ammonia levels, nitrite, phosophates, dissolved organics and whatnot. You'd have to "cure" that separetly in a bucket or other container until the dieoff is done, and ammonia/nitrite levels level out properly.
