To get to Merriweather, I would not recommend going up 29, that will be a nice big parking lot for most of the day. Better to come in 95 and take the 175 exit west, that road will follow around until it reaches Merriweather (after crossing 29 and then several lights). I park at my parents house and walk the mile there, but then again I am local.
I don't know anything, nor have heard anything, about tearing the place down, hell it has been around for 35 years, an institution, where the Who had a big riot in the early 70's. Some classic concerts were recorded there (Jackson Browne and I think Bob Seager). Yeah, not to everyone's tastes, but I did see the Replacements there, and lots of other cool bands.