While not in most tourists' game plan, Kentish Town provides some access to an area of inner London some may want to visit (I used to until the pandemic closure of a Wahaca restaurant right above the station).
The tube station will close for at least a year from the end of June. This is so the two exceedingly unreliable escalators (the worst statistically on the entire network) can be replaced and the whole station made nice(er).
Access to the Thameslink rail station will by the out of hours access - traditionally both stations share the same entrance and then for the rail station there is a bridge.