I do not recommend that any 'High Weald' cross-county constituency be created because: there are no real community links between Kent and any part of Sussex; the Weald line is the only real transport connection between these areas and it is not particularly good, especially with Southern running the trains at present, and also because of the disruption it causes in both the Tunbridge Wells and Wealden areas, whose internal links are sound.
Even though this would make Kent's constituencies oversized and the Sussex constituencies undersized, important geographical and community ties would be better preserved and therefore I consider keeping Kent and Sussex separate for the purposes of creating new constituency boundaries justified.
Instead of splitting Tunbridge Wells, the constituency should instead be extended to cover the entire district; keeping regard of local authority boundaries is important when designing new constituencies. No modification is needed to Rochester & Strood, either, and in many cases only minimal change is needed due to substantial differences between the smaller and larger constituencies of Kent (Faversham & Kent Mid has only 66,647 electors; Ashford and Folkestone & Hythe have over 81,000 electors apiece). This way, (mainly) coherent constituencies can be created, and Kent's new constituencies will be able to stick to local authority boundaries more.
My alternative constituencies for Kent within this review are:
Chatham & The Mallings succeeds Chatham & Aylesford.
Tonbridge succeeds Tonbridge & Malling.
Maidstone succeeds Maidstone & The Weald.
Herne Bay & Thanet West succeeds Thanet North; it stretches outside the Isle of Thanet hence the name change.
Canterbury & Faversham succeeds Canterbury.
Thanet East succeeds Thanet South.
Gravesend succeeds Gravesham.
Sittingbourne & Sheppey and Rochester & Strood are both unchanged.