Machine shop guy here for over 40 yrs. Brian's advice is spot on! In the past I have resurrected these kind of projects and lost(wasted?) more $ than I care to think about, not to mention wear and tear on my body trying to disassemble some of these projects that are supposed to be free (and spin free). My advice is to have the block pressure tested first, looks good enough to do that now. I would seal off the cracked cylinders, they can be repaired successfully with sleeves. The bottom of the block near the oil pan rail is the concern area. That too can be fixed by filling the block up to about an inch from the bottom. If it passes that test I would tackle the valve guides then seats. If you break through machining for a valve seat the block is basically junk, 'almost'. It could still be welded... Then I would sleeve it.
If this was a rare engine it would be a 'fun' project. Or you could purchase some equipment and have at it!