The route is predominantly 45/70 linespeed (don't know what the RA is for the two linespeeds, I assume the EMUs are ok for the higher speed).
Exceptions;
Faffing at Strood
45/60 through New Hythe
40 southbound and variously 20/40 and 30/40 northbound through Aylesford.
30 through Maidstone West (15 platform 1 loop)
40 through East Farleigh
45/55 from East Farleigh to Yalding
20/30 through Yalding
back to 45/70
45/50 through Beltring and approaching Paddock Wood.
30 Paddock Wood approach.
IIRC the route is signalled with 2-aspect colour light. No idea of the gradients, likely quite gentle - Paddock Wood is about 10-15m above sea level.