Awesome,
I usually keep my rucks between 35-50lbs depending on how I am feeling that day. Todd Bumgardner (Pack mule training) has some really good insight on the diminishing returns on rucking over about 25% of your bodyweight.
If you want to add a little variety, single arm or odd object carries are great for a few reasons. Think single dumbbell or kettlebell (don't go heavier than you can hold while staying upright) or bear hug / over the shoulder a sandbag, your ruck, whatever you can come up with. Great for building stability and core while also giving you the stimulus of a ruck. Weight depending, I'll usually go up and down my street accumulating about half a mile alternating sides.
If you have access to a sled, same deal. Sled pulls are the cheat code for building leg resiliency and muscular endurance without loading the spine. Something like a Rogue E-sled walking backwards will destroy your quads like nothing you've experienced. Like the loaded carries, I usually go abut half to 3/4 mile per session.
Lastly, adding in rotational work to prime your core / back etc for all the awkward moving under load that the mountains will throw at you. Kettlebell windmills, Turkish get ups, rotational Kettlebell RDL.