The only problem with this is, how to choose which cache to display? You could go with the closest to you, but that might be a 5/5, when there's a 1/1 a mile further away. Or you could go for the lowest D/T combo, but that might be a 1/1 which is 20 miles away, when there's a 1.5/1.5 a mile away.
In terms of the D/T matrix, there wouldn't be the above problems, but what if the closest to you hasn't been found for a year and seems to be missing? You'd not then be able to see others of that combo.
Instead of only showing one of each, would it be possible to have a checkbox for each D/T or month, which highlights that D/T or month on the map in a different colour, without having to refresh the page? Then you could see which caches are which.