i too was seeking info on this location about a year ago on this site. i recieved an email from someone who was on here the directions he gave me are. it is on private property in the NE 1/4 of sect 28, TWP 22N R1W ripley county Mo.
to view the site take highway 142 west of doniphan , after the community of Ponder turn south on P follow P south and west until you meet a small gravel road #Z-2AA. you will then go north about a mile.(i think it was a little bit more than a mile) where the road curves toward the northwest stop and look to your right. the hollow or valley before you will be the site of the Pulliams farm and spring.
i did take a drive down there right after a rain and was glad i had a 4 wheel drive as the road was very soft in a lot of spots. after seeing the area it is easy to understand how the 3rd was able to come up on them without being seen. i can not say 100% that this is the site, there was no one around to check with.. i hope this info is helpful. mark