Amboise is accessible

 by motorway :

A10 (Paris - Bordeaux) exit 18 at Château-Renault, A28 (Le Mans, Rouen) exit 20 at Tours, A85 (Nantes - Bourges) exit 11 at Bléré
 by train :

TGV from Paris to Tours, TER Center (Orleans-Tours)

 by plane : lowcost regular lines departing from London, Dublin Port, Marseille. Arrival at Tours airport