This will allow you a free return journey anywhere on the Northern Network, so long as you travel only on Northern Trains (you'd have to buy a ticket for any non-Northern elements of the journey, if there are any). These don't have an expiry date, and can be used as either as a same-day or open return ticket (up to 30-days after the outbound journey) so long as the dates are entered on the voucher for the outbound journey.
Please access the following link to download an up to date map of all Northern routes:
https://www.northernrailway.co.uk/travel/network-map
By utilising a really good planning website called Fast Journey Planner (
http://www.fastjp.com/#new?) you can plan a journey to and from anywhere, and more importantly you can select to either use only or exclude certain rail operators, so if you enter your preferred journey, click on 'Transport Operators', select 'Only use Selected Operators' from the menu and then select 'Northern', when you then hit the 'Search for Trains' button it will only find journeys that include Northern trains, and no other, making it easier to plan a trip and make the most out of your vouchers. This will only plot a single journey, to don't forget to plan your return as well.