I suggests to watch the weight of the vehicle during this buildup process.
For an capable travelling and offroad vehicle, you should try to keep your vehicle light, to keep the center of gravity as low as possible, to keep the weight between the axles balanced. What we should always keep in mind is the maximum legal payload.
If we look at the 3.5ton class, from Land Rover, Land Cruiser and Mercedes G you can mostly add 500-1000kg on weight to your vehicle. On modern cars they often use the basic edition inside of the papers - on the weigh station you see some kilos more than described. At first you should weight your verhicle, add the weight of the travellers to the bill.
Now let us look to the stuff what would be nice to add. From making the vehicle to an more capable offroader, to the stuff we need on an extended trip.
Far bad tracks and terrain one of the best mods are bigger tires to add more ground clearance under the differential. Now the spare tyre don`t fit below the car, we need a spare tyre holder in the rear (on top of the vehicle. So one mod often cause the next mod.
The following list is not complete, it shows also just the basic stuff, with an estimated weight. Often i use very lightweight equipment here, to find camping chears & table for just 15 kilo - is not easy at sample.
You get back some kilos from this bill, because you can remove the 2nd and on some cars too the 3rd row of seats. This bill is as it is in the 3.5 ton class. It dosnt matter if you sleep inside of the car, on a roof tent, a popup roof or on a ground tent.
You can just have a fully modded offroader for weekend trips, if you try to stay legal. If you add the stuff of the column to the right "internal building" - then you exceed what is legally possible.
If you attach great importance to a legal vehicle in the long-term travel trim, it is therefore advisable to stay close to the original vehicle configuration. To select the desired extensions wisely.
I`m pretty shure that you think now: what the hell - how all these others was able to travel extended with their beautiful modded cars? The answer is simple: they drive overloaded.
Also if in the papers the weight you can carry is limmited, many cars can take a much higher payload. How much they can carry, you can see on the armored versions of your car, who drive with the same axles and frame. I dont want to say: hey easy, overload your car. I just want to point to the reality. Try to travel light!
Look how is the weight between the axxle, look during the buildup that your car is well balanced. Try to use the ratio between the axxles, if it is documented. Look too that the center of gravity is low as possible.
In general, you should always save on weight where it is possible. Overloaded to be on the road is one thing, but nevertheless it is important to save every kilo of what is possible. In the terrain you are happy with every kilo saved.
At the end of each stop and rebuild (and only then) you should weight the vehicle again, fully loaded with all travelers. Now comes the most important: The suspension must be designed for this travel weight.
Of courset this are peak loads, where the diesel and water tanks are finally not always full to the brim (empty tanks are a good method for a quite legally drive in your homecountry. Nevertheless, you will always try in an environment with poor infrastructure to be as well supplied as possible, exactly where the bad roads are.