67 C20 Disc brake/suspension rebuild advice

[R.O.B.]

I'm want to accomplish a few different goals and not waste money in the process, but I need to do things in stages as money comes by slowly.

I have a 67 C20 that I inherited a few months back. It had been sitting for 19 years. It currently has manual drum brakes, manual steering, and 4spd manual transmission.

So far, I've replaced the fuel tank, pump and carb. Done the water pump, t-stat, cleaned the cooling system. I rebuilt the 4 wheel drum brakes, with new master cylinder, drums, seals, wheel cylinders, springs and shoes.

I still need to rebuild the suspension, but it's drivable for now. I also want to convert to power disc brakes in the front, and planned to use 73-87 spindles. This way I can purchase dropped spindles in the future if I decide it needs to be lower and I can save up the money.

1-So in the meantime, can I replace any 67 steering stuff and still do the conversion? Or do I need to convert all at once?
2-If I convert the spindles, inner/outer tie rods, can I use the 67 center link, or do I need to use the 73-87?
2a-If I need to use 73-87 center link, will it work with my current manual steering pitman arm, or do I need to convert to power steering at this time as well?
3-Can I still use my manual master cylinder, or do I need to convert to power booster/master cylinder at this time?
4-Do I need to change the hard lines out to a larger or smaller size?

Like I said, I just trying to figure out the best approach in stages.

Thanks,
Rob