BTDT ,several times over the decades on small gas engines on riding mowers. Drill small holes at ends of cracks, Nut and bolt patch over top,with JBWeld mushed in between block and plate. Replace conrod, clean out the sump,reassemble, add oil, good to go.
Have seen several gas farm tractors repaired with patches screwed on. You do what you can, with what you got..do it right, it'll outlive you and your kids....
Maybe get them side by side, with their own parts benches. Take stuff off one, then remove the same stuff off the other, go back to 1st, take more off, then take same off the 2nd. It might go faster as you're using the same tools doing the same procedure twice ?
Slow and steady and you'll win. You have to have patience and not get frustrated. When you do, just go 'walkabout' for a bit. And take pictures, it'll really help when reassembling