Allen C Perkinson Airport/Blackstone Army Airfield (KBKT) in
Virgina has a control tower, at least part of the time. It also
has class G airspace to 700 ft AGL.

What are the procedures for operating at a tower in uncontrolled
airspace? When are you obligated to communicate with the tower,
other than touching the runways? I don't recall this being
discussed much during flight training way back when.

How common is it to have a tower (other than a special temporary
tower, e.g. the one during EAA Oshkosh or AOPA fly-in.) without
at least Class D airspace?