Put the nights in the right places
This route has frequent room changes and some backtracking through Milan. Stay in Verona on day three, Lake Como on day four and Siena on day seven. The Vatican is an outing from Rome. The southern coast needs a ferry or road connection, so the complete journey is not all by rail.
Plan the visits
Venice · Verona · Lake Como · Florence · Siena · Rome · Naples · Sorrento · Amalfi Coast. These guides explain the current ticket choices, arrival points and useful areas for a room. Reserve the visits that matter after checking travel days, with arrival afternoons left flexible.
Shorten the trip
Reduce moves by choosing either the lake or Verona, and either Siena or the Amalfi Coast.
Build the budget from nights and days
The day figures add up to €2,643.00 for one traveller before the extra costs below. Day notes show accommodation, meals, local travel and small extras. The private-room line buys the whole room; divide only that part when sharing. These are chosen allowances, not measured averages or available room offers. A Vatican day uses the existing Rome base, and its local journey is within the local travel allowance. The final day has no extra overnight allowance in the Italian section.
Add paid visits, excursions, intercity tickets and airport travel. Replace the stay amount with the full booking cost, including taxes and cleaning. The city budget cards are an alternative way to plan the same days, so do not add them on top of this subtotal.
Plan the Vatican entrances
Use the separate Basilica and dome guide and Museums guide. Keep the existing Rome room and local travel allowance; paid visits are additional to these day figures. A dome booking can place Basilica access before or after the climb, so follow the actual voucher.