Forces in Fujian are already prepositioned and forces in Guangdong and Zhejiang are a few days away at the most. I wouldn't be surprised if ammo and nonperishable food is already stockpiled. Wheeled vehicles like logistics trucks, artillery, rockets and SAMs can drive on existing highways at highway speed (~100 km/hr). They can go from Guangdong and Zhejiang to staging areas in Fujian within a day and organize/load pallets of cargo within 2-3 days. People and light cargo can travel on civilian high speed rail specialty cars.
There's a reason why PLA buys much more wheeled versions of armored vehicles like IFV (ZBL-08), artillery (PLL-05, PLL-09) and rocket launchers (WS) than US or Russia which prefer mostly tracked vehicles. Unlike US and Russia where there is a huge need for tracked vehicles (since US is going to fight in 3rd world countries with shit infrastructure and Russia has snow/ice/mud that make wheels useless), China uses wheeled armored vehicles for rapid deployment on domestic highways. Tracked vehicles have a hard time traveling for long distances on highway and usually must be transported by rail, with the limiting step being loading and unloading at rail yards, driving to staging areas, then driving to the battlefield. Wheeled vehicles just drive on highways.
I envision the ground mobilization consisting of 1.) immediately activating garrisons of prepositioned units with tracked vehicles and prepositioned ammo/food 2.) shipping operational personnel for tracked vehicles and infantry by high speed train within hours 3.) wheeled vehicles drive themselves at highway speed within 1 days driving distance (~1000 km) 4.) further tracked vehicles shipped from inland within a few days 5.) followup ammo, food and supplies head for Fujian within 1 week.
