Not sure what the market is like in Costa Rica but here are some pointers that I follow when looking at a used vehicle like a 60.
1. Body rust or frame corrosion issues-this is a huge issue here in the US, some regions are worse than others.
2. Mechanical health engine: Engine compression and leak down test, leaks (coolant, oil and power steering), receipts for maintenance.
3. Mechanical health driveline: Driveshaft health, transmission shifting, clutch age, transfer case operation
4. Brakes: rotors/drums in spec, hard and soft lines in good, serviceable shape, brake master cylinder/booster in good shape
Big red flags for me are non OEM items in engine bay( besides a possible engine swap, as long as it was executed well), non brand name suspension and brake upgrades, light bars and major undercarriage damage from off road use. Some minor scratches are fine but bigger damage is worrisome and demonstrates poor driving technique which could impact other systems. I'm sure others with chime in.
Good luck!