As far as the driveway goes, the information I am providing is what the construction crew did when they built my house. I had them put in the driveway as well.
1. How much topsoil should be removed?
They cut off all of the top soil and eventually used it around the house.
2. Do I need a weed blocker? What kind?
They didn't put any weed blocker down. I either spot spray the areas or else get a 5 gallon bucket and pull the weeds. Usually there aren't that many but my driveway is only a little over 200 feet long.
3. What size stone should be used as a base?
They used black shale which makes an excellent base and is a less expensive than stone. I can get a tandem of shale for about $80 as opposed to over $200 for a tandem of stone. Shale looks like slate and comes in large flat pieces but breaks easily and compacts really well.
4. What size stone should be used on top of the base?
They put crusher run on top of the shale. It packs really well too. After about 3 years my gravel drive way is packed down so much that it looks like asphalt in places. The downside to crusher run is that it tracks in the house very easily.
5. When calculating how much stone you need, how do you convert cubic yards into tons?
can't really compute that as you are comparing weight and volume. Different types of stone and moisture content will adversely affect the ratios.
6. Do you build the crown before you lay down the stone or after?
My crown sort of built itself in from all of the heavy trucks going in and out. They had a slight crown but the trucks really made it pronounced.
7. What is the best tractor implement to maintain a driveway?
I have tried using a grader blade in the forward and reverse positions, box blade, landscape rake, steel roller, front end loader and lastly a railroad tie acting as a drag. The railroad tie did the best job and cost the least!!!!
Good luck