The Thames path is an easy route both in terms of ground and route finding. Minimal ascent, 5m to 110m in 180 miles, with a few minor ups and down along the way.
Finding camping sites would be difficult along parts of the route. London is a big city and like all big cities the usual precautions should be taken with wallets etc.
One walker reports he could only get a cheese roll in the "Anchor and Hope" on a Charlton match day.
After the Erith rejuvenated waterfront the path passes along the river isolated and hidden from view, see security.
After the historic Crossness pumping engines the riverfront is lined with the new flats that are a feature of much of London's Thames nowadays.
This general pattern repeats itself at the next bridge "Tadpole Bridge" with its "Trout Inn".
We overheard a telephone conversation with the landlord "Yes sir, this is the Trout Inn, are you sure you have the correct one........
I would suggest doing the first section from the barrier (and the extension - which around Erith has the additional issues of isolation from view, lack of escape routes and proximity to a population centre ) early in the day and in company, taking particular care in the stretch just upstream of the "Cutty Sark".