Holland, or more correctly the Netherlands is one of the most bike friendly countries in the world. The Dutch have a highly educated population, the majority of whom speak very good English. A fair number of organisations support and promote bicycling including the Automobile Association the ANWB. So along with some very good websites (but in Dutch) which show the details of how to get around the ANWB offer a variety of Dutch maps from 1:100,000 to 1:50,000.
For armchair planning purposes we think the 1:100,000 and 1:75,000 is the best though you may decide to buy finer detail maps when you get there. In reality the finer maps are not needed as, on the ground you will find many large maps (A3, A2 or A1) stuck on posts and numbered junction indicators on maps and on posts.