Reddit mentions of Guardian Fall Protection 01360 VL58-100 Standard 5/8 Inch Thick Rope with Snaphook End, 100-Foot

You will not be unprotected on your initial climb in if you use a line launcher or something similar on one side to put a line over the cross of your roof to the other. You then tie the rope in to a fixed point on the other side (like a tree or car) using a sling.

I used a kong ball with a hole in it (https://www.amazon.com/KONG-Ball-Dog-Medium-Large/dp/B0002DHOJA) and tied a thin 100 lb test nylon rope to it then launched it across with a dog ball launcher (https://www.amazon.com/Chuckit-Classic-Launcher-Colors-Vary/dp/B00006IX59). Once the small nylon rope was across the roof, I then tied it to a 100 foot 5/8" rope (https://www.amazon.com/Guardian-Fall-Protection-01360-VL58-100/dp/B004EEPTDG) and pulled it back across the roof so I could safely tie in.

It adds a few minutes to the time to get on the roof but it is worth it as you will have very low risk of falling because you will always be tied in.

I also use fall protection whenever I need to get up on a ladder on my 2nd story home. I have several different anchors that I can hang ropes from depending upon where I need to work.

You should also always be tied in moving anchor to anchor, something like this comes in really handy if you need to move across a larger roof: http://www.fallprotectionpros.com/guardian-big-boss-dual-leg-lanyard.html

This is a great video for finding rafters when you nail the fall protection in:
https://www.youtube.com/watch?v=OIMEMffezwI

All in all you would need to buy:

• 3-4 permanent roof anchors
  
• Some kind of line launcher
  
• 100 foot rope and optionally sling unless you have a connection point on the other side
  
• Fall protection kit with 50 foot rope and harness
  
• Shingle remover to lift the shingles before you place the anchor under them.
  
• Roofing adhesive to seal the shingle back down when you are done.
  
  When I did this on my home I:
  
  
• Secured one end of the 100 foot rope on one side of the house.
  
• Line launched a lighter rope to the tied off 100 foot rope. I then tied the 100 foot rope to the light rope.
  
• Using the light rope I pulled the end of the 100 foot rope across the roof to the other side of the house.
  
• I connected into the 100 foot rope and used it to ascend to the roof peak
  
• I lifted the shingles and installed the first anchor in a rafter, finding the rafter using the hammer location method.
  
• I then attached into the newly placed anchor using the 50 foot rope so I could safely move on either side of the roof.
  
• I resealed the shingles using roofing cement.
  
  If your shingles are older this job will be tougher. Old shingles tend to tear instead of lifting.