wow..... damn lucky kid, I wish they had deals like that in the boonies...
I'd stick with the 2.8L or the 4.0L, the 2.9 only offers about 35 more HP.... and you will need to do a lot of work to make that a 4wd...
the 2.9 is known to have some issues, the 2.8 is pretty durable, needs rebuilt after 100,000 usually. I go like this: If the engine does not need rebuilt after 75,000 miles, it will need it at 100,000 miles, if it needs a rebuild before 75,000 miles, it needs replaced. (this is based on if the engine itself breaks down, not stuff due to speeding, overheating, etc.).
The 2.8L with a standard is geared pretty low, you can get some pull and "umph" out of a 2.8L ranger when is stock.