Matt said:

Can trees grow succesfully in 100% sandy soils, with just a few inches of
topsoil, as long as there is adequate moisture? Due to the high water table
in the area, moisture shouldn't be a problem.

According to the huge and unwatered Norway spruce across the street from me
the answer is yes. I would be most concerned about locating your specimen
in the higher filled area of your yard as Norway spruce, while generally quite
tolerant of soil conditions, will die in wet soils.

You might be better off removing only a little of the sand and tilling in compost,
rather than carting so much sand off for topsoil stripped from who-knows-where.
You could be bringing in a host of problems (like nutsedge and horsetails or other
pernicious weeds).

--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)