I have no experience with the Ready Ref Sheets, and little experience with Judges Guild products generally. Back in the day, I was rather distainful of the Judges Guild material, as it seemed amateurish and of dubious value. The only Judges Guild products that I owned were Dark Tower, and the Fantasy Cartographer's Field Guide (the later having been given to me by my parents as a christmas present). Recently, I came into possession of the re-imagined Necromancer Games Caverns of Thracia (originally published by Judges Guild) and the Judges Guild Campaign Hexagon System and Village Books I and II.
While Caverns of Thracia and Dark Tower are both exemplary products, and have bona-fide "old-school adventure" credentials, the value of the Campaign Hexagon System and Village Books I and II accessories seems less clear. The majority of the 60-page Campaign Hexagon System accessory consists of blank mapping hexagons. The Village Books are similar in size and design, but those two accessories provide a map of a small village on each hexagon map (most villages in the books are very small, perhaps 10-30 unidentified buildings).
Pre-made Village maps, and blank maps upon which you can design your world, have some value. The value is in simply having a hex map with which to build your world, or a pre-generated town for the players to interact with and explore. But as I reflect on the thoughts of other old-school bloggers, I am increasingly convinced that the true value of those three products lies in the supplementary material and random generation tables contained within.
The Campaign Hexagon System accessory contains 6 pages of interesting supplementary material, and several random generation tables related to world-building. Those include hydrographic features (running water, along with unique water features like springs, quicksand, and geysers, river blockages, and river-flora), random prospecting tables, tactical movement rules using the map hexs, a page of eleven movement obstacle tables, two pages of twenty-two flora tables, and a page of sixteen fauna random generation tables.
Village Book I is similarly equipped, with nine pages of supplementary materials and random generation tables. That includes wall and street characteristics, random shop-type generation tables (modified by town size and government type), village-naming tables, and a "building materials" table.
Village Book II consists of nine pages of detailed heraldry tables and illustrations, to allow for the creation of unique and meaningful shield embossing.
I have had a change of mind regarding Judges Guild, and regret not having explored their other products earlier. I am intending to purchase the Ready Ref Sheets as a pdf from RPGnow or another on-line retailer. Are there other Judges Guild products I should be considering, in addition to the Ready Ref Sheets, as accessories that contain random generation tables or other valuable supplementary material? Are there any other "must-have" Judges Guild adventures, in addition to Dark Tower and Caverns of Thracia?