I've built most of my wheels in the past using a bike frame in a work stand or just hanging by ropes before I owned a work stand. Brake blocks or thumbnails are adequate to indicate side play. The only special tool I have is a dishing gauge to center the rear wheel. Even that can be achieved by eyeball. I've built several wheels in campgrounds for ACA tour group members on picnic tables and bikes hanging from tree limbs.
I roll my eyes when I hear the phrase "art of wheel building". Lacing a wheel is basket making 101 as long as you have the correct spoke length. Tensioning is a bit trickier but is not rocket science.