In my '60's, I would sometimes take three cameras and lenses with me. My K10D and K5...both with battery grips and both with extra batteries and my Km. All with lenses of course. After a couple of times of that, I thought enough already, that doesn't make sense.
But then I hit 70 and I find my work cut out for me, with my K1 alone, battery grip and extra battery and usually 100mm Pentax F 2.8 Macro lens or my Pentax 24-70 F 2.8.
I haven't had a precipitous loss in strength.
No, but I do have arthritis in my shoulder....so much so that I am scheduled to have an operation in the next while to replace my ball and joint so I won't experience the pain that prevents me from functioning as well as I'd like and am used to. So I adapted to my new health issue, planned what I could and couldn't do and carried the minimum.
I should be able to handle the K1 mit lens and my small Ricoh GR ll after I have recovered from the operation, however I think one camera should be enough..
But no more three cameras at one time. That will be too much and beyond me at this point. I should also be able to handle...singly...my K5 and Sigma 150-500.
I walk daily to maintain fitness. You sound like you have done very well, losing 25 Kgs and that takes a lot of discipline and will.
If your fitness level and health is up to handling the K1 and 24-70 then I would say go ahead. However as others have said, sometimes finding a bag or strap system which makes carrying equipment easier, might be in order.
As far as a tripod goes, I have an old Leitz Tiltall which I've used since my medium format film days. It is rock solid, but heavy. To carry it, I use a soft rifle case that I bought years ago and strap it to my back.
I don't carry the Leitz much anymore, and now, I'm not sure I could do so for any length of time. Perhaps a lighter, carbon fiber tripod that is stable when in use might be the solution.
What I've done in the recent past is figure out what I want to take pix of, figure out what is the minimal amount of equipment to do so, then select equipment that fits the bill. I try to ensure no extraneous amount of equipment will go with me. A kg. here...a kg. there...all adds up when you're hiking. Or at least it does for me.
So figure out the minimum you need for the photography you plan to do on a hike, possible look at a carrying system to alleviate the weight and don't over estimate what you can do. If you find you have overdone it in the weight of equipment, it will certainly wear on you .