Someone at this link: Loudwater: Secomber has sketched out a map of Secomber. Based on what, I do not know. WARNING: slightly NSFW picture on same page.
I don't think TSR or WotC has ever commissioned a map of Secomber. I couldn't see one in any edition of D&D going all the way back. Knowing a little about Ed Greenwood, I have no doubt that he has a Letter-sized page with a pencil sketch on it of the village, but I don't know him well enough to ask him for it.
Here is what has been said of this little stopover village on the road near the dangerous moors: