You could try flushing the fluid and see if it works OK. It's a long shot, but you're only out like $50 in fluid. Sometimes it will make things worse. How many miles are on this transmission?
In Texas, your rig might not fight the pull as hard as rigs do up North. Unless you've done it recently, pulling the tranny can take 6 hours or so - nearly the same for re-install. If you get anything wrong in the build, you'll be repeating those steps. You need to plan DAYS of time.
The teardown takes some meticulous care - make sure you have a workspace sufficient to lay out each of hundreds of pieces in a way you can get them back together in the same order. You must have a good manual. Before deciding to tackle this yourself, study a manual and see if you have the stomach for it.
As for parts, the best case is that you can have the rig down for some time. Then you can tear down, assess and then order parts. You can order a super rebuild kit ahead of time, but you may still find some issues that require more stuff. Ask around for a good local tranny shop that will sell parts to you. Otherwise you'll be searching eBay and
www.drivetrain.com and waiting for shipping.
There are plenty of useful special tools. Sometimes you can improvise and make something that will work (I've resized plenty of teflon seals with electrical tape, for example) but there's always the chance you'll get stuck. In some cases, you can leave well enough alone and not disassemble some stuff, but this kind of takes an experienced eye. Again, you may be able to take a subassembly to a tranny shop and beg some help. You might also be able to find a local CK5 member with something?
In the end, it's up to you. If you pull it off and have success, you won't have any fear of anything automotive in the future. If you don't have success, you might end up taking a box full of parts to a tranny shop or buying a used tranny somewhere.