Training for a 50k - splitting up time between indoor rowing and long runs

Hi - I'm training for a 50k in December. My training plan is currently:

2x long runs each week 4x 1hr steady state rows each week

I'm thinking I'll do 30miles of running and 170W of SS rowing (~56km or ~35miles of rowing) each week the first month, with the last week of each month being deload. And possibly bumping up to 35miles/175W, 40miles/180W the next two months. Peaking 2nd or 3rd week of November with a ~33mi training run with some friends, then ~3 weeks of taper.

Is this insane? My thinking is I want to maximize cardio, and minimize stress on knees/tendons/etc but not too much that I don't have the leg strength I need for long time on feet. IT band/shin splits/etc injuries are what I'm worried about most.

I've been training somewhat seriously for ~2 years now, running off and on my whole life, but never have really strictly followed a training plan. I completed a marathon late last year, ~3:52, HM PB ~1:35.

I just did my 1st long run of my 2nd week of this plan and am recovering nicely. But little discomforts in my legs have come and gone that I'm keeping an eye on.

Thanks