Hi, Beatrice,
In my experience, you will have absolutely no problem finding lots of vegetables, especially green beans, broccoli, carrots, potatoes, and chove (I think that's the name -- it's a leafy green like turnip greens8). The Portuguese are very fond of soup, usually have a bowl before every meal, and lots of those soups are purely vegetarian (unlike Spain, where little bits of meat are almost always thrown in). You are not likely to find anything much more than plain boiled vegetables, nothing too fancy, but the quality is generally excellent and only rarely do you get them terribly overcooked.
If your comment in post #6 means that you also eat fish, you will have absolutely no problem, because the fresh grilled fish in Portugal has got to be its best culinary offering. Robalinho and dourada are two of my favorites. Just get them grilled, they'll come whole to the table (split if they're bigger), always accompanied by a few potatoes and a cooked vegetable, just like Kiwi-family's picture shows. The olive oil is also outstanding, IMO, in fact my children always fight more over the Portuguese olive oil I bring back than the Spanish. Bom caminho, Laurie