Thanks, LJ BOY, Jeep is a passion for many of us! Welcome to the forums...
The TJ Wrangler was the pinnacle of traditional Jeep utility 4x4 development during the inline six-cylinder era. Each refinement from the 1972 CJs forward is notable. The YJ Wrangler took the Jeep 4x4 into the semi-modern handling era, the TJ advanced both handling and axle articulation to new levels with its link-and-coil suspension. The LJ Wrangler provided CJ-8 Scrambler loyalists with the best of both worlds: a Quadra-Coil suspension Jeep utility 4x4 with a 4.0L AMC-design inline six-cylinder pushrod engine that offers reasonable serviceability and makes it possible for 'DIY' owners to work on their vehicles—a Jeep 4x4 tradition!
You cannot go wrong with any 2004-2006 LJ Wrangler Unlimited! An '06 would provided the very last iteration of the TJ/LJ. Powertrain wise, any of these years is reliable and distinctively stout, although the cylinder head has a bad rap for its "emissions compliance" tuning and port design. Coil on plug ignition is reliable for the most part, and the transmissions, either a 42RLE automatic or NV3550 five speed manual will deliver. The 42RLE has the major advantage of an overdrive fourth gear to match the NV3550's 5th gear overdrive. This distinguishes the final generation TJ Wranglers and LJ Unlimited models.
Note: Our friends at Advance Adapters offer the Rubicrawler two-speed reduction unit for the 42RLE automatic TJ and JK Wrangler models. See this unique product and how it can really enhance these model 4x4s: http://www.4wdmechan...J-Wrangler.html. Here is an excellent tour of the Rubicrawler by Steve Roberts at Advance Adapters. I interviewed Steve at Paso Robles, CA in early 2013: http://www.4wdmechan...Techniques.html.
Of course, the LJ has the distinct utility of a long bed or cargo area and still only two doors. Arguably, this is a "true" LWB Jeep utility 4x4, although the JKU Wrangler Unlimited has certainly redefined the Jeep 4x4 with its four doors!
The ideal would be a TJ Wrangler Rubicon edition for its 4.0:1 low range ratio and Dana 44 axles front and rear with factory lockers. When I was the host at the Mopar Tent/Camp Jeep events, I continually encouraged owners and prospective buyers to consider the TJ/LJ Rubicon edition for its factory equipment that meets most reasonable off-road needs. The 31" diameter tires, mild factory lift, axle differential lockers and heavier duty axles are often sought in the aftermarket at considerable cost. If you find a clean, well documented LJ Wrangler Rubicon, buy it!
As for documentation, history is everything on a used vehicle, especially a 4x4. If at a dealership, ask for service records and a CarFax. If a private party purchase, ask for as much documentation as possible. Service records, mileage and an ownership trail are keys...Glad to comment on any prospective purchase.