Progressing furthur

i started riding laps of of richmond park as it's only 6 miles away for me, started with 1-3laps now i do 4-6 depending on how much time i have. i now find it easy to do 50 miles so that longer road rides of 60+ aren't so daunting (or knackering).
i recommend good shorts and not carrying a bag if you do those kinds of distances it's much more comfortable. proper bars are much better too as you get to move your hands around a lot and get down on the drops if it's windy or you want to go faster.

endurance is built up by steady 70% output riding. i.e. going as fast as you can but still being able to hold a conversation without interfering with your breathing, if you go balls out fast straight away you will be pooped. hills naturally give you a short intense period to vary your training.
i don't actually see these rides as 'training' it's just the chance to ride more so that on proper rides i'm able to keep up with the geared riders

i've done a bit of running in the past (last year) and that was a similar approach. I even went off the drink (what the fuck) and took it pretty seriously. ie 4:30 wake ups 12 and 3 mile runs...12 jogging (as you say so i can talk) and 3 mile runs.

I entered a race not too shortly after my training, a 10k which i did in 40:41 for my first effort at running i was pretty chuffed... but i think my body is not made for stamina.