I would not try to wash an unquilted top in this condition. Aside from dyes bleeding and seams fraying, it's quite possible for the fabrics to shrink at differing rates. This would create a distorted top that can never be ironed flat again.
What I would do is place the top in a garbage bag with a pair (or two) of Dr. Scholl's Odor-Eaters shoe inserts -- the ones made with charcoal. Leave it alone for a couple of weeks, then check. I did this with a featherweight case that had that moldy basement smell and it worked very well. Charcoal absorbs bad odors. Using Odor-Eaters means you don't risk getting charcoal on the fabric.
After the top is quilted, you no longer have to worry about uneven shrinking of fabrics. Quilting binds the three layers so that the batting takes control of shrinkage. Assuming just a moderate amount of quilting, the batting does not allow any fabric to shrink more than itself. (This does not apply to quilting that is 12" apart, or to tied quilts. In those cases there is not enough tying the layers together, so the fabrics can still shrink at uneven rates.) You also do not need to worry about frayed seams.
As for bleeding, you really do not want to soak a quilt unless you are sure no fabrics will bleed. For a first washing, it's important to use a washing machine that uses a *lot* of water (so any dye bleeds are diluted well). The large front-loaders in a laundromat are good for this. However, as I mentioned, you want to do this only after the top is quilted and the quilt is bound.
Edit: Just an added note. You do not want to lay a wet quilt or wet top over clotheslines to dry. Water is very heavy and puts a lot of stress on the stitching. With a top, the added weight of the water can break thread, especially if the top is hand-pieced. With a quilt, the quilting thread can break. It's better to dry a quilt or top flat. A finished quilt can also be tumble-dried in a large dryer.
One more edit: I would want to reinforce any holes in the top before layering. One option is to hand sew small appliques over the holes.
Last edited by Prism99; 05-05-2013 at 10:28 AM.