Having owned an XJ series Cherokee, I would not trust one for overlanding. This is just my experience, but mine was an absolute dog and horribly unreliable. It was in the shop more in three years than my Toyota or Nissan were in their whole lives. Some XJs seem to be bomb proof, but for every one of them there are 10 that are lemons. The problem with Chrysler is that of consistency, you never know if your vehicle will be one of the good ones or the rolling pit you throw money into.
For $5,000 I don't think you will find any Land Cruiser worth owning, they just have too much residual value and are desirable project cars. The only ones I see for that kind of money have more holes in the body than a colander.
Trucks are great because they are modular, but you can run into problems with dust getting in - even with a camper shell. My next vehicle will likely be a crew cab pickup.
The 4Runner is a solid vehicle, but for $5,000 you are going to be looking at a fairly old vehicle with higher miles. This is the problem with Toyota, everyone knows they are reliable and well built so they have a higher buy-in than other brands. Some of that price is deserved, some of it is just the badge.
When I was faced with this choice, I found Nissan to be the best bang for the buck. I was able to get a newer, lower miles vehicle for the same money. My XTerra has been very reliable, it turns 11 this year and I have loved owning it. The VQ motor is just as reliable as anything Toyota has built and has gone in everything from Z-cars to luxury sedans, to pickup trucks (granted with different cam and crank profiles). You should be able to find an early Gen2 XTerra for about that price if you look around and are not too picky about a few rough spots. A clean late Gen1 is certainly within the range.
Another option would be tracking down a Suzuki Equator. This was just a Nissan Frontier with a Suzuki badge stuck to the grill, but because it is from a dead brand (at least in North America) they often go for thousands less than the Nissan Frontier. Literally the only difference is the badge, it was even built in the same factory on the same line, by the same workers who built the Frontier.