I do feel there could be a link between the Julia James murder and that of Maria Rawlings.
Distance isn't so much of an issue considering that serial murderers average distance-t0-kill can range from less than a mile to over 500 miles. People are mobile and thus murderers are mobile. As America had a boom in serial murderers with the launch of highways, our own motorways, A and B roads facilitate killers further away from their immediate vicinities.
The location of both body finds are similar, though Maria Rawlings more suburban but still in green space where people walk their dogs. Both locations were metres away from an A-road (A2 in the James case, A12 in the Rawlings case). Both women lay dead in places where school-children might see them on the way home, on time for the post-school crowd.
The MO of causing death seems similar; both involved blunt-force trauma, although Rawlings also suffered neck compression. We haven't had full details of how Julia James died as yet.
The profile of both victims is not dissimilar. Julia was 53 and Maria 45. They're both white British, both from home counties, and both not at work in the afternoon.
The time the women were found/murdered is also similar. James supposedly left home around 14.30 and police were called at 16.08. Rawlings was found at 14.00. This is the post-lunch/pre-evening (13.00-17.00) time of day, when not much happens except to do with schools closing for the day.
If they are related, I'd look at the similarities between the victims, and the time of day as a key signal. If linked, there's a pathological need for the killer to viciously hurt middle-aged white women and leave them broken and exposed in time for the schoolkids walking home. It's broadly about 'revenge' but only in the pathological sense, against some deep-set long-ago 'wrong', and not directly against these women.
If these two cases were linked and I were to geo-profile them together, I'd say the offender is someone who would live somewhere with a buffer from both incidents, most likely London or the part of Kent closer to London. He's mobile for work reasons connecting Essex and eastern Kent. I'd look at Dartford, Maidstone and Bromley.
But if they aren't linked, and if there aren't any more similar killings within a 15-mile radius of Snowdown, then the profile would be the original disorganised offender suffering from psychosis. It would be hard to consider any other type of killer with that kind of short range combined with the disorganised nature of the murder. He would be somewhere in the triangle between Margate-Canterbury-Dover.