It is difficult to do if you're trying to get all your carbs from tubers/potatoes. My latest find is tapioca pearls, which I use to make tapioca pudding. Tapioca is made from cassava, a tuber, so they're a "safe starch" or whatever you want to call them, even though they're basically a refined flour.
If you allow white rice, it is also helpful in getting enough carbs. Asian markets also have rice noodles, paper, and other more "fun" forms of rice if you get tired of just plain cooked rice. Yes, these are all more processed, but they greatly help in getting the carbs you're shooting for.
Personally, I haven't tracked my intake or even set a goal number of carbs in a long time. I probably don't get quite as many carbs as would be recommended, but I think I do pretty good.