Mike,
Just because the heads are leaking doesn't mean they are pitted, and
need the "JB Fix"

The head seals can very well be cracked and leaking all by themselves.

You can remove the heads in the Van without dropping the engine.
It's not a difficult job at all, just time consuming.

Don't be afraid of it.
Attack the problem.
It's easier than you think.( if you have a good selection of tools, and
some wrenching savy )