Well although I just got a mm540 recently. I drove to chikmaglur the next day I purchased it. But before that here are the minor tweaks I performed.
Here is a tiny story. Hope it helps
Took it to a good mechanic.
Did a through check up of the engine oil, Brake fluid, Diesel pump, Fan belt, Brakes, But these were only the minor adjustments needed for a total distance of 400 kms back and forth drive in one day.
Although I am a newbie to jeeps on long drives. It was better than driving a car. Believe me you're going to enjoy your whole trip, Just relax while driving, enjoy the nature on the way, Keep a constant speed, say 70/60 kmps is pretty good and will give you a good mileage. If possible click some snaps of the scenic beauty and post it here. If you have bucket seats already in them it adds to more comfort, otherwise its ok too. As the jeep guru's here have said
"KEEP A BIG EYE ON THE TEMPERATURE" if it does go above 80C and stays there constantly? stop the monster and check for radiator water and top her up. Take a small break, start and drive slowly and see if it heats up. again if it does? Time to take her to a doctor. If you have been driving a car, getting used to the gear system might take some time, While sfifting gears you might hear that awful noise, I dont know what you call it but the gear sounds like its going to
"cough up" during shifts if not operated properly. Although the gear system is like the Maruthi's dont expect it to be smooth. I had the same experience myself. But now its chill.
The only problem I encountered while driving the jeep on my way back was heating of the passenger cabin, due to the wiring holes near the brake and accelarator pedals the hot air of the engine comes inside through here . You might want to check for these as it gets quiet sweaty and hot inside. If there are any holes you can fill it up with thermocol, and it will be as cool as ice
. Thats what I have done for the time bieng. and is my personal experience with my 5 day old MM540.
Also make sure you carry all the necessary genuine parts if available, Do not compromise on this, As suggested by other members, Because you never know what spurious parts the jeeps owner might have plonked into it, Which might go kaboom.