I was able to visit this site last April 2012, prior to its inscription as a WHS. By that time, I didn't even know that it was in the T-list! In fact, Bujang Valley was more popular at that time as a contender amongst locals.
Anyhow, the inscribed area is big - a bit scattered as well. Though some digs are open for visits, I never got the chance to see any of these then(at the moment, I've yet to hear a good review about these dig sites, so I guess its really nothing to feel sorry about). Nevetheless, I managed to see the museum that houses some of the findings in the area. I hope that some upgrading and modernization of the facilities in this site are on their way, though -- its really needed.
For some weird reasons, I didn't see the famed Perak Man in Lenggong Valley. I saw it, however, earlier that year -- as a guest article -- in the Sabah State Museum! I think that returning the skeleton back to Lenggong would make the visit to this site more meaningful and fulfilling. Furthermore, the valley is also scenic with its limestone karst backdrops.