Looks like a typical jeep at least where I am from, as long as there is not rust that you can poke your finger through you should be fine. That all looks like surface rust, which is fairly normal for a vehicle that is 14 years old. My dad's 98 Sahara doesn't look as nice as the one you are looking at underneath, but salt does awesome things to metal.
2003 Jeep Wrangler Rubicon
4.0L, 42RLE, Dual Tops, Full Doors, JKS Front Disconnects, Cragar Soft 8 Black Wheels, 33x12.5x15 Goodyear Duratracs, .75" Front Coil Spacers, Bushwacker 6" Flat Fender Flares, Skid Row Steering Box Skid, LubeLockers, Rubicon Locker Mod, OBA, Cobra 19 Ultra III CB, 3' Firestik, Rough Country 2.2 Steering Stabilizer, RC 1.25" BL, RC 1" MML, RC Grab Handles, Fog Lamp Bent Pin Mod, 4" Apline S Series Speakers, Kenwood Excelon 6.5" Speakers, 6.5" JL Audio 6W3V3 Subwoofer (in center console) w/MTX Thunder 202 amp, IPF H4 Headlight Housing, Sliverstar H4 bulbs.
In the rust belt, we call that "excellent condition." I didn't see anything that was terribly alarming in those pics. Obviously not a Cali born a raised vehicle, but nothing really bad. As long as the frame looks solid, that bit of surface rust isn't an issue.
However, unless you're getting a steal of a deal, there should be plenty of completely rust free examples around you to choose from.