Is that ranch still there ?
No it is not... the website link I provided above has all the information on its history, and current status of the site.
and how close was it to Columbia's lot ?
GOLD RAIDERS was not a Columbia production. An independent production from Bernard Glasser, originally intended for distribution by Columbia, but distributed instead by United Artists.
Chatsworth CA is in the Valley, 25 mi. north of downtown Hollywood.
("Hollywood CA" + "Chatsworth CA" + most-any internet map program = 25 mi., driving directions, and a map)