I was looking for places to stay near Thorne if I were to do the London->Thorne DIY 300 later on this year.
There's a Travelodge at the M18/M180 junction between Thorne and Doncaster, but the only access is by Motorway, not even a local service road (like Membury/etc).
But you can get to within 50 yards or so along some farm tracks off public roads.
I stayed there before/after LEL last time, and we also used it as a doze stop on the 2006 Easter Arrow
I can confirm that you can get through to the services that way. My advice, based on experience:
Don't drink a skinful after a 1400 k event and fall off your bike in the pitch dark at about midnight, dropping your car-key (with it's easily-identifiable up-market car-maker's logo) on the rutted and overgrown farm track (which leads to
exactly where your car is parked) , necessitating a return to the spot for a frantic search at first light - before anyone else - instead of the anticipated post-LEL lie-in.
Don't startle the couple in the car parked on the lane, thinking they'd found a quite place for a shag, and not expecting the midnight arrival of 5 randonneurs with Solidlights ablazing