Ok, yes, YJ's are much cheaper and easier to swap a rear axle under compared to the TJ. However, it still requires welding of leaf perches and shock mounts. Cherokee D44 would be a good swap as well as the Explorer 8.8 (95 to newer for the rear discs) or the Cherokess 8.25 is another though its not a well supported by the aftermarket with gears and lockers. Make sure if you go with an 8.25, you pull a rear axle shaft and count the splines. 29 is the upgrade and stronger axle compared to the 27.
Anyways, leaf perches are readily available aftermarket or at your local truck shop (over-the-road, heavy-, medium- and light-truck shop not your 4wd accessory shop). Same for the shock mounts, but again, aftermarket would have them ready to ship out.
You'll have to prep the next axle by removing all its suspension mounts. Then bring it under your Jeep. New ubolts should be used to secure the leaf to the perch and axle. Check you rear ds to the yoke to bolt in and your brake lines for adaptability. Once you determine your pinion angle statically, then spot weld the perches. Do the same with the shock mounts. Remove the axle and weld in the mounts. Then install. Bleed brakes, attach parking brake, check or change fluid, attach rear ds and your ready to go.