Canada doesn't salt like the U.S does so Canadian trucks tend to fair much better than northeastern U.S trucks as far as rust.
The 2.3 is a great motor but check for signs of coolant at the back of the engine. There's a coolant line on the back that never gets replaced and if it's leaking it requires pulling the transmission to fix. Check for oil in the spark plug wells (just pull a plug wire and see if its wet at the tip). The valve covers are known to leak there and are also somewhat annoying to fix. The PCV valve is critical on these engines and again never gets replaced because of its annoying location. Service records are a good to see if these things have ever been addressed.
Oh right! The 2.3 motor... so how 'bout this... guy selling it is the original owner. When I asked him which engine it had, he says "a 4 cylinder", which is why I wrote the 2.3 4 banger...
I go to see the truck, and the owner fires it up to move it out a bit from where he had it stored. I'm thinking, that does not sound like an inline-4.
He pops the hood, and clear as day, 4.0 L SOHC. I point at it and look at him with a big grin, and he's like "what?".
Unfortunately, the interior was a bit worse for wear, and it had a couple of electrical issues. Probably nothing major, and kudos to the seller for being upfront about them.
I've since turned my attention to an '07 XL 3.0 V6 with only 119K kms and looks to be in great condition inside and out. This one's an automatic with power windows and mirrors, which are a pretty nice feature when people of different height will be using the vehicle on a day-to-day basis.
As for the 3.0 vs 4.0, I've read spools of threads extolling the pros and cons of each. In the end, I won't be towing anything, and most of my driving will be in the city, so I'm happy to sacrifice the power of the 4.0 for the reliability of the 3.0 (not that the 4.0 isn't reliable, let's not start that up again).