Depends if you value your comfort or not, if you do then it has to be a Disco, older TDi Range Rover. Defenders are OK but good ones tend to be expensive and they are worse on fuel due to the gear ratio's, I'll get flamed for this but Defenders aren't what I'd choose as a long distance cruiser in the comfort stakes.
On all landrovers the chassis at the back is the place to spend most time poking around - it benefits least from the oil leaks. Check for water leaks into the car or evidence of them, make sure you start it from cold - if they have warmed it up go back another day check the radiator / top of engine with your hand, turn the key and check that all the test lights illuminate and extinguish as they should (read up on the model you are viewing) get suspicious if any don't work, test drive should test all gears including high to low shift and diff locks if present though these are hard to test on the road.
Have a good look over the car and see if you can spot the signs of care or neglect - you generally can, don't be afraid to walk away a Landrover can be a money pit especially an older one that has been subjected to questionable or zero maintenance - Landrovers are a high maintenance vehicle.
Alas this is a sort of howdy thread not a how to buy FAQ - Google is your buddy as is the search between new posts and quick links in the bar above.
Howdy ... maybe.