In Batman Begins, Bruce Wayne created everything he needed to become Batman in the damp, empty cave under his house. He had some help from Lucius in getting materials and the Batmobile, and of course Alfred was there. But that's it. He had to do everything himself because the world can't know he's Batman. And each item he owns -- from his weapons to his suit -- is filtered through his company as being for some other purpose, the modifications made with his own hands.
But we're going to go out on a limb and say that Bruce and two elderly men with shovels are not going to be able to build this:
We're estimating at least three broken hips and one pulled Bat-groin to make this happen.
That's the most small-scale version of the Batcave ever portrayed, from the old TV show (they didn't have Joel Schumacher's budgets back then). Someone will surely pipe up in the comments to point out this is the new, gritty, realistic Batman, so they'll surely have a scaled-down, gritty, rebooted Batcave. But that also would make no sense. If the new Batcave turns out to just be a workshop and a couple of laptops hooked together, why even have a Batcave at all?
The whole point having a cave headquarters is that his crime fighting equipment is too big to fit in his enormous mansion, so he needs an entire sub-structure -- itself the size of his whole mansion -- to keep his Batman stuff. Hell, look at the size of his temporary digs: