It's worth more than I am willing to pay!  Nice!

I would not be surprised if there were some offers from this community, especially if you share about its provenance.  We like stories.  

Very interesting indeed.

I guess the next step would be to establish whether this is the tournament module, or the actual manuscript for Holmes Basic.

There are 3 stages of this particular manuscript.
The 1st looks like this:

This version is a huge folder stuffed with handwritten pages, typed pages, photocopies, lots and lots of corrections as well as some crude illustrations by JEH and some great illustrations by Chris Holmes (which were submitted to TSR and I am surprised they were not used in lieu of some of the art that was).
This one is staying in my collection and will not be sold, so pleas do not try. You can see how excited I am about it here.

The 2nd is an intermediary stage between the one directly above and the one in the initial post.
It is a cleaned up photocopied version of the above with numerous hand corrections/notes. Still includes a rough layout and illustrations by Chris.

The 3rd is the one that I posted here for appraisal.
It is a clean typeset document with no corrections or illustrations (other than the dungeon layout).
There are multiple copies of this version with at least 2 colors of outer cover (blue & gray).
The Holmes family retained one for their master set of Holmes material.
I have 2, one of which will be up for grabs at some point this summer.
And 1 (or possibly more) would have been sent to TSR where it was probably lost or destroyed since none have surfaced yet.

Thanks for the additional pic and description, Billy. Fascinating.

As far as your original question goes - valuation is not my area of expertise, but I know it's difficult with these kind of unique items as it is hard to find comparable items.

A few other manuscript sales that I recall:

In 2004 at GenCon, a photocopy of Holmes' original manuscript for the Holmes/Kuntz article in Dragon #12, and correspondence between them, sold for $180. See here. Obviously a rulebook manuscript is going to be much more valuable than a magazine article draft.

A Dungeon Masters Guide (1979) manuscript, a review copy owned by TSR employee Jake Jaquet, once sold for over $3000. I'm not sure what year it was, but stratochamp mentioned it in a 2011 post here. There was open bidding (on Ebay?) on that item between three Acaeum members so that's a pretty accurate value for that particular item at the time it was auctioned.

Chris Holmes said that there should be an illustration of a carrion crawler too!