Congratulations Nathan, now the fun begins. Your tractor sounds like mine was when it was dropped off here. Clutch compartment full of water, tanks plugged, all controls and shafts seized.
The rear main on mine was seized so I ground it undersize on the rear four mains and built the front main back up to std as that's the only bearing size available from Cat. Basically spent a lot of time disassembling, shining parts up on the wire wheel, and that got 90% of the components back working how they should do. The rest were replaced, and I did basically all of the bearings and seals from the fan back through to the bevel gear pinion. Have not done the finals as they're stuck but that's next on the list after I get the main running, which is imminent. The pony is in the shop getting thrust washers installed on the crank.
You can take your leaf spring to a truck spring shop and they'll make you a brand new one. You can either replace just that leaf or, if you take the whole pack in, they can make you a new pack. The benefit of that is that you can assess how high your current pack sits, and then tell the shop to make the new pack an inch higher, or half an inch lower, or whatever you need..