on this site, there is a program called MOHAA Tools 1.4b. Use that to recreate a .map file out of the .bsp file you want. then load the .map file into Radiant and spend the next few weeks rebuilding the map. good luck.
yes but most of the brushs if they turn up are split into 6 ne brushes which makes it a nightmare to workon. you'll need a lot of time and paicence (sp?) so good luch and hope your sucesful.