True, the rope does become brittle after about 5 or 6 years. Yes we have used chains also, but the chains are more costly and heavier, we have found ropes OK if changed out every 5 years. I tell people that on my web site. As for squirrels eating the rope, hemp rope yes, but NOT poly prop rope. We use to use hemp rope, but it is not as strong, the sun damages it real fast and mice and squirrels eat it.

Sounds like you used a "system" similar to mine, I just wanted to share it, since I know when I was young that I didn't have a lot of money, loved to hunt and had little knowledge of how to safely make tree stands. Maybe you can use the Y-boards. Thanks for your advice on Chains, I will add this tonight to my "how to make Rope Steps" and say you recommend chains with hooks on the end. What do you use as hooks? Bolts with two large flat washers?
Chap Gleason