Travs, you are a very fit bloke so no surprise there! When the legs have had enough of running I can certainly see you making a top notch cyclist.
To a certain extent, the two disciplines complement each other. If you can climb well running, you are usually pretty good at the same on a bike. 50 miles is a good distance and not to be sniffed at - probably what I'd aim for on a Saturday morning easy ride. Cycling is generally about power to weight ratio - generating watts combined with stamina.
There is of course no equivalent of down hill running in cycling - well I suppose sitting to be exact! There is definitely a skill to descending though (and equal parts bravery as in fell running) but I do start to get the jitters when I hit 40mph.... 🙄.