Pick my next outdoor challenge; Part 3

This board has been fantastic in coming up with outdoor event and challenges for me to take on. I have until the end of the year to pick my next one so I'm here searching for ideas. Hoping to find something I've never done/ heard of before.

Many years ago someone here mentioned the Tour du Tech 110 mile kayak race. I had never heard of such a thing. I signed up, finished the race and loved it. I then went on and did the MR340 race. A 340 mile kayak race. I posted a thread here and linked my satellite tracker so people could follow along. After the race I mentioned wanting to try something different since there is no longer race in the U.S.

Poster LSUintheNW suggested climbing Mt Rainier. I had never climbed anything before, but I read up on it figured out how to train for it. I had a thread on here with my satellite tracking link when climbed it 2 years ago. It was challenging, but fun and I loved the view from the summit.

After the climb I was looking for my next adventure/ challenge in the thread about the climb. Poster JoJohammer suggested the Grand to Grand Ultra. A 170 mile self supported ultra marathon through the high desert areas of Arizona and Utah. Starts at the edge of the Grand Canyon and ends on top of the grand staircase. Loved the scenery, but I'm not a runner so I tried to kick the idea for 2 years. Never could kick the idea of the challenge so I trained for 10 months and was able to finish it in the middle of the pack last week. Feel pretty good about that since I had only previously run three 5k races and none of those were in the last 5 years. It was a grueling but fantastic experience. LINK to G2G video

Now I'm searching for a challenge for next year. Help me out OB. Looking for anything outdoors(off-road)that is endurance related that will take training, travel and several days to complete.

Note: will not consider the Barkley marathon. No guarantee of getting in and that's one I don't think I would enjoy or finish.