NP203 Part Time Conversion Questions

[Christiansok]

I'm looking to purchase either the mile marker 502 part time conversion kit with manual hubs or the full shaft replacement kit to convert my np203 to part time four wheel drive. After reading some walkthroughs on the conversion and a video overview I'm feeling confident enough to take on the project myself on my DD. If I do the conversion (shaft or 501/502 kit) with the transfer case in my truck how long can I expect it to take?

After talking to a mechanic my dad has used he said he's had experience converting them saying it would cost a couple hundred bucks because you have to tear the transfer case apart and it takes hours. From what I've read though people say with the transfer case outside the truck you can swap the components in an hour if you know what you're doing. This makes me doubt taking it to someone and wasting my money.

Looking though the walkthrough on colorodok5, http://coloradok5.com/milemarkerpt.shtml and watching this short video to see what I'm up against,

http://www.youtube.com/watch?v=AL2X5ppolVw

, I don't see this being a multiple hour, couple hundred dollar job.

So, if I go to tackle this by myself I have one very newbish question having never worked with drivelines before. How do I disconnect the drive shaft like the first step in the coloradok5 walkthrough shows?

Also, for four wheel drive vehicles it looks like the speedo gear is inside the transfer case, is this correct? My speedometer is currently 20% or so off because I have a 67-72 on a later 73-? frame. Would anyone know what color /teeth speedo gear is needed to make a 67-72 speedo work with an np203? Or should I just use the gear ratios/tire size and comparison of my speedo with a GPS to find the number of teeth I'd need (I'm planning on getting larger 33" tires right after the conversion)?

Any info/tips with the conversion and the speedo gear swap would be appreciated, thanks!

Edit:

I also forgot, which would be recommended for just a daily driver application, the 501 kit or the full shaft replacement?
Also how and how easy is it to replace the factory slugs with manual lockout hubs?