Are you pulling up a hill? Muddy/slick terrain? Do you have rear ag tires now? I would start with the easiest solution and work up.
1st - rear ag (bar) tires.
2nd - dual wheel adapter, with ags.
chains and weights accordingly.
I would personally forgo the 4wd and locking rear end, just for the significant added expense. (and time)
Keep in mind this will adding a workload to your transmission, fortunately the 2500 series is fairly stout....but I don't know much wood you're pulling and how often!
If this is an ongoing task, I would personally look at a 3000 series with diff lock, or up to a 4x4 subcompact.....understanding the cost increases with each level. The 3000 diff lock makes a huge difference over the 2000 series (having owned both) and the price is ~reasonably~ more.
Good luck!