I was visiting your web pages and came across the section on the "Ralston Rocket". I have to admit that I only knew of such a prize from "Kraft" foods for a marshmallow promotion. I have no date for the enclosed picture, but I believe it must be about 1955 or 1956 or so, judging by my size standing on the steps (dark shirt and pants). I only knew the rocket pictured as "The Blakely Rocket". It toured under this name for a chain of gas stations, later to be sold to "Gulf".
I don't know if this helps with the date, but I believe the "Blakely Company" sponsored the "Rocky Jones Space Ranger" series run on local TV at this time. I know this is where the visit of the rocket was promoted. This was in association with grand openings of new service stations. This may add to your mystery,if the mystery still remains and the question....just what rocket is this one ??? The Blakely Company operations where in the state of Arizona and this photo is from a station grand opening, somewhere in Phoenix.