As all of you family researchers have found that our ancestors did leave a paper trail of all sorts.We family genealogists just have to look in the right place to find that paper trail.
FYI be sure to look at the Bureau Of Land Management [BLM] records online as "BLM GLO Records" and take a peek at the folks there to see who shows up.
The earliest of the surname I have found so far is the following: BOSTOCK, Henry; with three (3) entries on 05 NOV 1833 for Calhoun Co AL in the White Pigeon Prairie Land Office.
BOSTOCK, George; with one (1) entry on 01 MAY 1839 for Calhoun Co AL in the Kalamazoo Land Office.
If you have the proper setup to print a copy of the "official" document you will have it for your files that will add to the records of your ancestor in a given place at a given time to show their "footprint" on a given trail.
FYI also is the four (4) entries of James B. BOSTOCK in St. Clair Co IL on 18 SEP 1835 at the Edwardsville Land Office.
And take a look at the listing of Charles BOSTOCK in Pettis Co MO on 01 AUG 1849 at the Clinton Land Office.
The ladies of the surname can be seen as follow: BOSTOCK, Ellen P. in Jackson Co IN on 01 JUL 1857 at the Jeffersonville Land Office. BOSTOCK, Mary; is listed twice. First, in Harrison Co IN on 01 MAY 1845 in Jeffersonville Land Office.Second, she is listed 01 JULY 1857 in Jackson Co IN and the Jeffersonville Land Office.
There are more BOSTOCK listed at this site with later dates of entries that may be of some help to you in your research.