Andrew,
You have received some excellent advice. First off, I second offwidth on the Training for the New Alpinism, excellent read, and it details how to become elite when comes cardio adaptations and suffering for long periods of time. However, that does not seem to be your goal. FWIW here is my opinion.
I would stick primarily with rucking and maybe add an LSD run below MAF threshold every 10-14 days. I have rucked and run extensively in my training and rucking seems to carryover better to any activity that has a strength component to it. Here is a little vignette (true story) to illustrate my point:
Person x is a marathon runner, running in the 3.5 hour range, he has stellar cardio. A sheep hunt is undertaken by person x and person a. Person a is a guide that focuses mostly on rucking with a little running and strength training mixed in. The mountain ascent is undertaken, person x only has a 25lb pack, which is less than the bare minimum to survive in the Alaskan alpine country, very shortly person x has a very hard time climbing the mountain, while person a is only having moderate difficulty while carrying a 75lb pack. A sheep is shot by person x, who now loads his pack to a whopping 50lbs (sarcasm inserted), and person a now has over a 120lbs. The walk out takes place and person x almost completely shuts down due to fatigue. Person a has to add more gear to his pack and finish the walk. In total only about 20 total miles were covered and a couple thousand vertical feet, and person x stated that if he had to cover another mile he would die.
Now, one could argue that this is an instance where specificity has taken place, but I saw it often in the Army as well. We had guys who could run 6 miles in 24-26 minutes, but put 25lbs on their backs and they could walk about 10 feet. On the other hand there were guys running 30 min 5 miles, who could throw a 100lbs on their back and walk all day.
Considering the fact that you are a landscaper I think rucking would suit you better and have a lot more carryover to your life. Personally I really like to do both, but I have noticed overall that rucking seems to have less of a biological cost on my recovery than running does, but that is just an n=1 sample.