Check out www.car-part.com
. It's where I found my '06 4.0 w/ 1,000 miles on it. It's an online database of a ton of junkyards and their inventories. check it out. I'm assuming you're after the 4.0L SOHC? If so, look for an 04+ engine. Alot less likely to have the timing chain rattle issues of the earlier engines.
You'd need engine w/ complete engine/trans harness, PCM for the same year as your truck now same options as your swapping to, transmission, exhaust Y pipe, and a trip to the dealer to flash that PCM to match your PATS key. That'd require a tow.
But I will say though...that 3.0 Vulcan you have now isn't just underpowered, it's a total and complete long lasting engine that's a total workhorse.