The headlights and dash lights have one thing in common; the headlight/dash light dimmer switch. The dimmer part of this switch can cause intermittent dash light problems. This switch HAS to be grounded. Run a good gound to the back of the switch.
Your headlight problem is most likely one of two things; 1. bad connection on the back of the headlight or burned out filaments or 2. dimmer switch on the floor.