Use http://www.bogglewords.com/us
Every 6 rounds will be a Theme Round, you have to fill in your letters in Bogglewords and if there is a theme that has only 5 or 6 words you can try to go through the words list to see if you can get it. It took me 2-3 hours to get a theme that was doable i think. The theme i had was Desserts: Cake, Cakes, Cheese, Cheesecake, Cheesecakes.