The 242 is a 24x series and it considerable larger then a 23x series. I wouldn't call it weaker, maybe to a 241 but not a 231. I don't really see why you'd want a 242 though. In situations when you're driving at in snow or sand, you can drive in 4wd without any problems. You'll just want to switch when you reach dry pavement. Problems with the 24x series cases, you'll need two new driveshafts. There were some SYE kits for 241's but I haven't seem them in a long time. The case is considerably longer especially with the slip yoke. So, you'd need to see if anyone still makes the rear seal/housing for 241's. Next, is the spline count. They always used 23 spline. You'll either need to locate a 21 spline or else have one made. The bolt pattern for the case is the same as the 231. People have sone the NP241 swaps well before the Rubicon came out. All have been on 4.0L's though.
I believe Mile Marker once made a viscous coupler that would bolt between the driveshaft and the transfer case but I don't think they still do.