Michelle Nolan wrote an article about ACG for CBM years ago in which she said that Adventures into the Unknown #70 -#79 had some exceptional material. They are also very tough to track down because of low print runs - but I did eventually find them and they are hugely enjoyable, just as her article had promised.
They are generally characterised by a combination of romance, fantasy wish fulfillment, time travel, mythology, spaceships, dinosaurs and alien races. The often poignant stories were almost all written by editor Richard Hughes. They featured Harry Lazarus, Curt Schaffenburger, and of course Ogden Whitney. Here is a selection of the best covers, all from the mid-50s: