In the time of The Elder Scrolls Online, Skingrad seems quite different from what we experienced in TES IV.
The Hightown district is missing! Currently occupied by vines.
The Chapel district seems more stretched towards the west. No doubt to compensate for the absence of the Hightown district.
The structure of the castle is very faithful (with the chapel) to what we knew in TES IV. However, access looks quite different.
Access to the castle does not seem to be possible from the location of the vineyards. However, it appears that there is direct access to the castle from the south gate, next to the chapel of Julianos.
I don't know where the Golden Road runs. In the CGI representation of Skingrad, a river appears to replace the Golden Road that runs through the city's two districts in TES IV.