The most recent guidebook doesn't identify places to eat or sleep in Alcobaca. There must be some? Maybe they are not so good? Open to your comments/suggestions.
There are a few hotels near the monastery, so check Google map, Booking, TripAdvisor, etc., to see if anyplace would work for you. We only spent a few hours there to see the monastery while transiting between Öbidos and Nazaré.
Look at Fodor’s guide book. Rick Steves guide books are not comprehensive and skip a lot of interesting places to visit.