The Leiden tourist office is just across from the rail station, I'd make it my first stop and buy a map. Ask the fine folks behind the desk if the restaurants below are still in business and have them mark the locations on your map.
If your company is paying the tab, the Rotisserie Oudt Leiden (Steensstraat 51) is very good and expensive.
Next door is the much cheaper 't Pannekoekehuis (Pancake house).
Near the town hall is Bernsen on Breestraat 157.
Don't be bashful about asking the tourist office for suggestions.
In The Hague, I like to take the tram (#9) down to Scheveningen. There are many restaurants along the Strandweg on the beach side and town side. They all post their menus and prices near the entrance, so there are no unpleasant surprises. Find one that is busy and in your price range and you are unlikely to be disappointed. I like the fish and chips, so I "dine" at one of the kiosks.