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 cycling including the Dutch 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 maps are the best, although you may decide to buy finer detail maps when you get there. In reality the finer maps are not needed because you will find many large maps (A3, A2 or A1) stuck on posts beside bike paths with numbered junction indicators on both maps and posts. This is as close to idiot-proof cycling as it gets.