I have my heart set on getting an old F250 or F350 PSD for both work on the property and for towing a camper/family on camping trips.

Example - Looking specifically for a 96 Ford 4-door diesel, or something similar. Would change it to a flatbed.. Open to other ideas, but budget is limited to something like 4-8K.

I don't have a ton of experience on older diesel trucks but I know we'd use the heck out of it. I need it on the property in a bad way - but because budget is limited, I need to focus on older/higher mileage.

Any suggestions or advice? What should I look for in these when I go to see some for sale? Blow-by, etc..?

 

With the powerstroke you want to make sure it fires up quickly and smoothly. They'll crank a bit before they fire because of the design, but should pop off within 2-3 seconds. Also make sure it's not loping or idling choppy. Either of these are not a major issue, just means it has some miles on it. Excessive white/blue smoke is not normal either, also if it feels sluggish down low, but seems to wake up only above about 2300 rpm or so the hpop could be telling its age. The engine will run a long time even with the symptoms I described, but eventually it'll need some love and diesel parts aren't cheap.
If it's an auto trans I wouldn't touch it with a ten foot pole, but that's just my opinion. Rarely do they make it 200k without being rebuilt, so just ask questions and ask for receipts.
i don't know where you live, but where I am you won't find a diesel for less than 8000 unless it's junk or 2wd. I have a 460 and honestly it pulls just as hard and maybe harder than the early powerstrokes. It just burns a lot more fuel. It's a lot cheaper to maintain though.