Good luck! I've found it difficult to do both, but that's because you end up needing to consume a ridiculous number of calories to keep up with it. I've heard the advice of a gallon of milk a day just to keep up with a full strength training routine alone.Running is still going on, and I've started a weight lifting training. Currently I'm running 3 times a week and lifting once or twice, I hope to switch that around in a couple of weeks.
Back when I cared about such things, I used to eat half dozen eggs in a typical day, albeit with most of the yolks removed, and I was losing weight. It's not so easy to put on weight when exercising a lot. One thing people often forget is that working out doesn't make you bigger. Eating makes you bigger. Working out helps you put the chemicals where you want them. The thing I notice most about getting older is how long it takes my body to recover compared to ten years ago. I got to a point where I would struggle to work out hard enough to make myself sore. Now I can feel it after a night of ice skating really hard. Part of that may be due to the fact that I'm not a gym rat like I used to be, but I also think I can chalk a lot of it up to age.