The transfer between KL1 and KL2 is a kind of bus-train, similar as in PAris-CDG, runs every 2 or 3 minutes, and its just a tunnel under the tarmac to the other side of the runway, takes less time in KL then a walk through Dubai-airport. Dont bather about that. The train is indeed to Central-station in KL, wich takes if i remeber good +30 minutes and costed soemthing like 20 dollar, hardly cheaper then a Grab !! Did several transfers in KL during the years, but all internatioanal-ones, even with 30 minutes layover, and was in time. Once my luggage wasnt in time and had the choice to wait 7 hours or they would bring my luggage the day after to my hotel here in PNH, what they did !! Cant complain about KL at all !!