Not to scare you... as I think the failure rate isn't a high % but people speaking about it is....
The NP200 original T-case "historically" does not take daily driving at higher speeds well. (It overheats in some cases).
The engine while up to the task, if daily driven regularly requires some maintenance and upkeep... of which spare parts can be difficult/problematic to find especially locally and in a pinch. (water/fuel pumps, carbs, generators, starters, distributors, etc etc etc).
Most approach it as a "run it until a problem arises" then address...
67' M715/5.9 Cummins/ZF5/NP205