I ran a 100 mile race while doing long cycle -3-5 times a week. I ran one while doing Simple & Sinister 5 days a week.
I've run one while doing a mix of both, plus body weight stuff.
Probably none of it made any difference specifically but probably most of it helped too.
I do know that I ran my first 50k after several years of heavy GS and very light running - I took about 3 months of specific training ultra training (mainly just double long runs on the weekends) while maintaining my GS routine (AKC - one money set, followed by some heavy one arm stuff) and ended up having a great first race experience and placed pretty well. I maintained this for a year or two all the way through my first 50 miler and after which I made some changes. Things became harder when I added speed work in, extra hill repeats and stuff to make me a better runner. My lifting suffered for sure. So I reached that point where there was a trade off and I chose ultras and did my best just to keep whatever strength I could. In retrospect, I probably could have done fairly well just continuing with the GS with only being a little bit slower overall. Now that I'm doing ultras with less emphasis on time and mainly just going for the finish I hope to gain some strength back. Just my experience.
Ericc, you have very impressive experience as a runner, wow! 100 miles seems pretty impossible to me right now. You say that you are still doing some ultras but when I glanced over your log it seemed like lots of walking and gymnastics...am I reading it wrong?