I like this goal for you right now. Getting out on the trails at this time of year will be great for the mindset. Yes it’s a short space of time but I think it’s possible as long as we don’t focus on pace. I like the idea of working to distance on this occasion. But that ultimately will be your decision, but plotting a route before you head out and just getting it done, regardless of pace, is a good mindset as an ultra runner.
Back to back weekend runs will be key. It worked well before and was a key part of Anna’s plan for the 50 miles. It spreads the load nicely and I think peaking at 22 miles is about right as you should recover quite quickly from that and it’s not too daunting.
As strength is a high score for you on the ratings (edit these if you feel they are incorrect), I think 1 S&C per week is still enough. Adding in daily stretching has helped my own running massively and something I would encourage. Also when time allows just to do some simple warm up exercises for 5-10 mins before heading straight out for a run. What’s 10 minutes if you’re going to be out there for 4 hours? They are worth doing.