My gut told me that it would be easy to plan for short stages on the Madrid. But since my gut was wrong yesterday when I ventured the opinion that short stages on the Mozárabe would be problematic (turns out it’s EASY between Almería and Granada), I thought I should do some actual tabulation. So...
Starting with my stages from years ago,
https://www.caminodesantiago.me/community/threads/my-leisurely-stages-on-the-camino-de-madrid.11148/ I came up with one option. I just used gronze with my stages as a base, but doing that showed me that there are many other ways to do this, because the accommodations on the Madrid (assuming you can splurge on private places) are quite plentiful. To start with, the albergue infrastructure is excellent, and when you factor in towns with hotels/pensiones, your options increase a lot!
Day 1 — From Church of Santiago to Fuencarral (the town, not the street). That would be about 20 and there are places to stay there, none cheap. OR you can hop on Cercanías train for a few minutes back to Madrid and then come back out the next day.
Day 2 — Fuencarral to Tres Cantos (13)
Day 3 — Tres Cantos to Colmenar (10)
Day 4 — Colmenar to Manzanares (15)
Day 5 — Manzanares to Cercedilla (20) — can also be split with a stop in Mataelpino, where there is an albergue
Day 6 — Cercedilla to La Granja (21)
Day 7 — La Granja to Segovia (8)
Day 8 — Segovia to Añe (20 km) (also easy to shorten with a stop in Los Huertos)
Day 9 — Añe to Santa María la Real (12)
Day 10 — Santa María to Nava de la Asunción (13).
Day 11 — Nava to Villeguillo (17)
Day 12 — Villeguilo to Alcazarén (17)
Day 13 — Alcazarén to Valdestillas (16)
Day 14 — Valdestillas to Simancas (15). (Here I would also recommend a detour into Valladolid if you like medium sized Spanish cities. This is a very nice one, with a beautiful barroque monastery turned into the Spanish religious sculpture museum). Buses to and from both Puente Duero and Simancas are frequent).
Day 15 — Simancas to Peñaflor (21)
Day 16 — Peñaflor to Castromonte (9) (five star albergue, as are many of them on the Madrid!)
Day 17 — Castromonte to Medina de Rioseco (15)
Day 18 — Medina to Tamariz de Campos (12)
Day 19 — Tamariz to Villalón (14)
Day 20 — Villalón to Santervás (16)
Day 21 — Santervás to Sahagún (19)