During an unsupervised solo instructional flight the pilot, who recently received an instrument rating, planned on increasing his flight time in hopes of becoming a commercial pilot. The pilot indicated to ATC that he had received the local ARPT weather. A broken ceiling was reported at 2000 ft AGL (2800 ft. MSL). The pilot took off and flew northbound toward mountainous terrain. After flying for about 10 min, the pilot radioed ATC and indicated he desired to return to the ARPT. ATC issued the pilot a clearance which he acknowledged. The pilot did not indicate that he was experiencing any problems, nor did he request assistance. There were no further communications with the pilot. Witnesses located about 1 mile from the crash site reported observing the ACFT flying in and out of clouds in an easterly direction next to a mountain. The ACFT appeared to reverse course, and it initially commenced flying in a westerly direction. The ACFT then turned to the north and headed toward the mountain which was partially cloud covered. The ACFT disappeared from view upon reentering the clouds, and seconds thereafter the sound of an impact was heard. The crash site elevation, 8.3 NM from the departure ARPT, was about 2550 ft MSL.