All the London railway stations :
Underground lines : Northern, Hammersmith & City, Metropolitan, Circle, Piccadilly, Victoria. National Rail, London Overland. ThamesLink
Accessibility friendly : Partial.
Hammersmith & City and
Circle lines eastbound towards Liverpool Street (A step 150mm/gap 6mm),
westbound towards Edgware Road (A step 167mm/gap 13mm).
Metropolitan line eastbound towards Liverpool Street (A step 127mm/gap 33mm), westbound towards Harrow-on-the-Hill (A step 160mm/gap 63mm).
northbound towards Camden Town (A step 50mm/gap 75mm), southbound towards London
Bridge (A step 50mm/gap 75mm).
Piccadilly line eastbound towards Oakwood (A step 123mm/gap 0mm), westbound towards Heathrow Terminal 5 (A step 169mm/gap 34mm).
Victoria line northbound towards Tottenham Hale (A step 41mm/ gap 81mm), southbound towards Brixton (A step 43mm /gap 85mm).
(National Rail) There is lift access between street and platforms.
General description : Kings Cross is a very large National Rail station, with links to many Underground and Overland routes. The concourses linking the various sections are generally flat, but expect travelling some considerable distance between the different lines. All platforms are now step-free; but gaps and steps onto train lines are listed above for the Underground lines.
More comment :
Sometimes - Victoria & Northern.