MCL rehab

Four years ago I had a very bad 1st degree MCL tear during a skiing accident. I had the leg elevated for the first week due to all the bleeding and swelling in the leg, and the MCL scarred down nicely, but I also had anterior and medial swelling that wouldn’t go away. I kept revisiting my sports med physician and told him that something else was wrong, they even did an MRI but the partially torn meniscus went undiagnosed. Every time I would do some sort of aggressive exercise the meniscus would swell up again to the point I could barely walk. They finally scoped and cleaned up my meniscus, and with proper rest and rehab, it would recover, but during any aggressive activity, I always experienced some swilling, and I ALWAYS carry a portable ice bag and elevate right afterwards. My only regret would be maybe I didn’t do enough therapy while healing, because when I try and sit in a lotus position, I cannot put my right knee flat on the floor. I’ve since quit skiing and taken up snowboarding because it feels more fixed and stable for my knees, and quite frankly I like it better. Three weeks ago, I tweaked my left MCL (my good one) and didn’t pay much attention to it as it got better after a few days. I just spent 7 out of 8 days boarding while on a ski vacation, I bumped into a tree on the anterior side. It still is bruised and sore from the impact. I’m experiencing some of the same pain as before, but w/o the bleeding and swelling.
Same symptoms, everything. I don’t want to go the whole doctor route as I’ve been doing RICE, but I’m concerned about losing the same stretching and mobility that I did when I tore my right MCL. I’m wondering if anyone can suggest some home grown physical therapy and stretching that will prevent this from happening?