Google Maps has great route planning tools for car journeys. They also have full public transport data and will show you Public Transport itineraries (with maps) if you choose the "bus" logo under "Get Directions".
Derbyshire County Council have a webpage where they note road closures and other problems caused by bad weather - updated around 7am on days when there are issues.
If you are planning to use public transport extensively, do have a look at the one-day Derbyshire Wayfarer ticket. This covers most buses and trains in Derbyshire (and offers entrance price discounts at many attractions), for £12 adult (with one free child), half price for additional children and pensioners - or £22 for a group of up to 2 adults and 3 children. You should be able to buy the ticket on the 172 bus that goes through Winster, or you can buy in advance from Tourist Information Centres (you scratch off the date when you decide when to use the ticket).