Like Thomas said, as long as the Wagoneer is not a celebrity-quality example, a straight across trade for the J-truck is a no-brainer, at least IMO. J-trucks in good condition are scarce. The 258 and automatic (TF999 I believe) will be rather pokey though. Good swap material, IMO.
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk