With tourist juggernaut Florence just a few kilometers down the road, Prato doesn't bother offering much in the way of hotels. If you're traveling by rail and staying at the Hotel Giardino, ask the conductor if the train stops at Prato's secondary station, Prato Porta al Serraglio, and get off there, because it's closer. For the hotels San Marco and Flora, get off at the main station, Prato Centrale.
You might try the San Marco, Piazza San Marco 48 (tel. 0574-21-321; fax 0574-22-378; www.hotelsanmarcoprato.com), a modern but not new hotel overlooking the Henry Moore sculpture halfway between the train station and the Castello; doubles run 90€ to 95€ ($117-$124).