Yeh I have stayed at the riverside travel lodge before, we also walked. I think the best way is through the retail park in the direction of the roundabout, think you can jump out somewhere there, then over the footbridge. It is a bit of a treck, but when you are going to be sitting down for hours its a nice walk on a sunny day.
Usually knackered by the end so its a taxi back, but only costs like £3