I started 2 April this year. Orisson was not open. The Napolean route was still closed due to snow. I walked via Valcarlos and stayed there overnight. I booked SJPdP but it wasn’t necessary unless that is you have a favourite place you’d like to stay. Ditto with Valcarlos. There were still empty bunk beds in the municipal albergue. Similar situation at Roncesvalles. Most of that month was quiet if not staying in the major
Brierley end stages. The wonderful exception, as
@Camino Chris said, was Semana santa when absolute madness reigned but it was the most fantastically blessed time to be on the camino.
Next year Semana santa is in March so no worries about that. I am envious. I loved walking in early spring. Wishing you a very buen camino.
PS If staying in albergues, don’t listen to anyone who might tell you that you don’t need a sleeping bag.