Boulder Mountain is a popular destination because it offers fast fishing in dozens of small lakes. It is similar to the Uintas, offering some lakes that are accessible via rugged dirt roads, while others can be reached only by hiking or backpacking. A few of the lakes contain trophy-sized brook trout.
Lakes on Boulder Top usually become accessible in early or mid June, depending on the mountain snowpack.
See DWR's Lakes of the Aquarius Plateau booklet for good but dated info on these lakes.