Here is the link to the latest info on White Mtn, etc:

http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5404138.pdf

Notice the recommendation to use high clearance vehicles. I have driven the White Mtn road many, many times in the past 35 years, and would never attempt it in a small sedan, like my Honda Civic, but have no problems driving it in my Jeep Liberty. The condition of the road can vary considerably month to month. If the lab has been using trucks to transport equipment and supplies to Barcroft Station, the road surface can be damaged by the heavy loads. I heartily recommend that you rent a 4X4 SUV! Call White Mtn. station before setting out. Just a little friendly advice from a local...

The views from White Mountain Peak are stunning and well worth the hike. You might be able to visit the lab if they are not too busy. One of the newer projects there is a study of the background radiation from the "Big Bang." http://www.wmrs.edu/projects/astro-UCSB/default.htm

Link to Barcroft Station: http://www.wmrs.edu/facilities/bar/default.htm