I take it by core you mean weights/pressups etc? What intensity was the 4 hr ride? Im just trying to get a feel for your current level of fitness. I wouldn't call 35 mins an endurance ride. Do you mean high intensity? Im guessing the sore legs is due to delayed onset of muscle soreness, usually happens after a' heavy workout' and can take a few days to recover no matter what you do differently.Just do whatever you can do when this happens. Do a longer turbo session but at an easier pace. I dont find stretching before or after helps although some people swear by it. For your body to recover you need the nutrients and calories and lots of sleep. For me I eat a lot of sugary/fatty foods but also big balanced meals as I do quite a lot. I feel better for it. I have tried eating good stuff and dieting and I just dont take enough calories in and training becomes laborious and gains, if any are minimal. If you are relatively unfit ignore the last sentences,eat sensibly and just do as much as your body feels like doing.
I find running once every 2 weeks and/or football initially gives bad Doms but after a couple of months I very rarely get the soreness and can train virtually every day whatever exercise I do. It has improved my overall fitness massively. Training indoors is doing you no favours either, you want to get better on the bike you have to get out and ride, interval training on turbo or outside should help with the soreness in the long run. I spent 2 years confined to gym stuff 4-5-6-7 times a week and performance gains were very very very slow but weight did fall off, that's my experience. I find detailing training and food habits in a blog (
http://crimmey.blogspot.com/ ) on paper can help so you can see whats working and whats not and adjust as necessary.
There's a good thread 'how to improve overnight recovery' which has some suggestions you might like to try out.