One of the ‘problems’ when discussing the Roman Fort is the lack of real knowledge about what it exactly looked like due to the later construction of the Norman Castle and Keep and to a degree evidence destroyed by the Victorians during the construction of the rail viaduct. To prove the shape would mean the demolition of the Castle Keep, former Northumberland County Offices, Bridge Hotel, railway viaduct and the Moot Hall, something that isn’t going to happen any time soon. However the latest thoughts on the size of the fort are that it was somewhere in the region of 95m x 67m – as it would have followed the outline of a cohort fort it would have been roughly rectangular in shape, roughly as it still had to fit within the confines of the promontory.
The number of troops accommodated at the fort is also debatable as no barracks have been discovered on the site.
On the matter of the fort’s location is still a matter of conjecture as to whether it was part of Hadrian's Wall, perhaps controlling an access gate.
Of course the name often associated with the fort is Pons Aelius but that in real terms relates to the river crossing over which it guarded, Pons Aelius being translated as ‘Bridge of Hadrian’.
Whilst the promontory looking over the Tyne gave a good defensive position to protect the bridge it was not a site that the Roman military engineers would have immediately chosen as it did not give ready access to deploy the garrison. This was due to the steep cliffs on all but the western side of the site. Thus the ability for troops to pass in and out of the fort was very restricted and thus this idea of the conventional gates associated with a Roman fort was not one found here.
Of course “real physical presence of the fort” does survive, albeit concealed beneath the area of Castle Garth and much of it has been revealed during archaeological digs, the last being in 1996.
Not sure that the Roman army engineers would have needed to do much in the way of having ‘levelled off this hillock’. There was certainly archaeological evidence of ploughing (ardmarks) of the land in the pre-fort period (narrow rig and furrow). Unproved but the site may well have been the site of a settlement prior to the building of the fort.
On the matter of the ‘Old Newcastle Project’, perhaps you are missing the point – this is a specific project dealing only with the area of the Black Gate, Castle Keep and St Nicholas’s Cathedral Church. Worth taking a look at the projects web site @
http://www.oldnewcastle.org.uk/old-newcastle-project
You mention a ‘visitor centre’ well that is one of the functions that Black Gate will perform – this is from the above web site:
Heritage Lottery Funding has been secured to create an accessible, heritage-led education and interpretation centre in the vacant and closed Black Gate, transforming its current lifeless and substantially ignored presence into a hub of heritage activity that will be open and available to the entire community and visitors from near and far. The Black Gate will combine with medieval neighbours, the Castle Keep and St. Nicholas Cathedral to provide an outstanding and dynamic heritage asset that will tell the story of the remarkable history of the City and the ingenuity of countless generations of its inhabitants.