The sand is a pain to wash but so worth saving the money! I love the way it looks in the tank!
It's a killer to wait while doing a fishless cycle, but it will save you a ton of work and headaches of constant water changes if you don't invest in a water changer.
I would do a bit more work on the dw before just adding the tank. First does it have any bark on it? If it does and it doesn't easily peel off, It needs weathered for most likely another year. Just toss it outside and leave it there till next Christmas. Next push your finger nail into the wood does it leave an impression or does it have give to it? If it does toss it and don't use it. You don't want any soft wood in your tank. No elm, maple, birch, or any type of evergreen woods unless they are 10+ years old. Soft woods have a tendency to leach a lot more than tannins which are safe and in fact the fish like. What fish don't like are the saps and other toxins that they are prone to leach in to your small enclosed glass box. Once you get past that then you have to look at processing the wood to make sure it's free from gunk and bugs!
1) scrub the wood to make sure you get rid of all of the dirt and lose bits of wood. Then you have a few choices on how to actually kill anything that may still reside in it.
a) boil it. Boiling may damage the fibers in the wood making it weak and it will break down faster in the tank. Pro it saturates the wood so it sinks better! Boil anywhere from 20 minutes to 4 hours. Then soak the wood in a separate bucket for no less than a month to make sure it doesn't rot and foul your tank. No reason to mess up your tank and have to break down the entire thing just because of dw that rotted in your tank. You'll know if it's bad because it will smell really bad! 50% of wild driftwood will rot if left in water like this. I find it's much easier to clean a 5 gallon bucket then one of my 37g tanks. This is the method I use. My last piece I soaked for almost 3 months.
b) Bake it at 250F for 6 hours. This keeps the integrity of the wood fibers intact but it dries it out so much that it take forever to get the dang things to sink. Still needs soaked for a month to make sure it doesn't foul the tank.
c) Soak in bleach water for a week then another few days in prime water. This may actually damage the wood fibers the most out of any of the methods. I also and again needs soaked for a month to see if it will rot and foul your tank.
These might take a long time but I have yet to be in the group of a people with a rotting stinking sludge infested tank with dead fish.