I have an advance ticket which includes a WMR train and according to the WMR website there will be no services on the line in question at all. What are my rights if I choose to travel and complete the journey by alternative means (e.g. get a lift from a friend, as it is not very far)? Travelling on another day is not an option because I don't suppose WMR will cover two extra nights of accommodation.
If you no longer want to use your ticket and would like a refund, you are entitled to that. You won't struggle to get it, in fact they will try to imply it is your only option.
What is your journey? Based on your previous comments I'm assuming it involves somewhere like Kenilworth? If so then presumably there are still services for the remainder of your journey?
If you still want to use your ticket, you are entitled to alternative transport for the unserved portion of your journey. No doubt WMT would try to deny this if you ask beforehand, on the grounds that "there's a strike" or "it's been advertised". However, neither of these facts change their legal responsibility to provide alternative transport under the NRCoT and the Passenger Rights and Obligations Regulation.
I would suggest you are best off asking them in writing to arrange alternative transport (e.g. via social media), and when/if they refuse, make your own reasonable arrangements (retaining the receipt) and submit a claim for reimbursement to WMT after your journey.
Obviously arranging a lift from friends might be easier but you will probably struggle to claim back any petrol money etc. for their journey because it's tricky to quantify an exact cost they have incurred. As bizarre as it sounds you may be better off getting a taxi -
if there aren't any suitable bus or coach options.
That would be on top of any claim for delay compensation if you are sufficiently delayed - again, something they're likely to refute, but they cannot exclude the liability for statutory delay compensation under the PRO. They try to exclude it under the NRCoT but in the circumstances I think they'd very much struggle to establish that this was a fair term in a consumer contract.