OK sorry I read your post wrong. I thought you meant 6200Ahr of batteries, instead it was 6x200Ahr or 1200Ahr @ 24V (which gives the 14.4kWhr number in the provided link). I should have been more specific in our case we have 12V batteries in 48V chains, total energy capacity is 24kWhr (12V * 20 * 100Ahr). So your system should be just ok but without much spare capacity, depends how much stuff is always on.
A generator is nice, as long as that system can start/stop it automatically, but who is going to fill up the fuel tank?
The technical specs at the link you provided are a little thin, i.e. no details about the inverter, it is probably ok powerwise but you should get more info before buying.
Batteries from Alibaba are around the 100USD mark for 12V 100Ahr (1.2 kWhr) last time I looked (doesn't include shipping).
EB