2016 4Runner: towing, gravel, and highway tire advice

Hi there!

I have spent hours researching tires and am a bit confused about the load range rating scale and how it applies to my use of the 4Runner. My tire rating and size is 265/70R17 113 S, 32 PSI.

I currently have Nokian Rotiiva AT, 115 T, D. These tires have been discontinued and for some reason, all the A/T Nokian tires offered at Kal Tire no longer come in 265/70R17.

I commute roughly 1000 KM a week in the 4Runner on dirt, gravel, and pavement (I hope to purchase a commuter vehicle in the next 12 months, but for now, this is my ride). In the summer months I tow a cargo trailer and utility trailer, roughly weighing 2500 lbs of dirt, mulch, quad, or water (maybe once a week or so). I do not do any hard-core off-roading, but do travel on back, camp, and fire roads. I always buy all terrain and all season tires, even though I do switch them off for a dedicated winter tire. I live in Alberta and it can snow at weird times, so I prefer to have the three peak tire that can handle snow in September.

Because I drive a lot on gravel, Fountain Tire recommended the Good Year Wrangler Workhorse AT, with a Standard load range, which I believe is equivalent to 4 ply or B. I feel that this tire is too weak for my needs, however this same tire in a 10 ply seems overkill. My biggest concern is the summer towing. Do I need a C,D, or E tire for towing? Would the recommended Workhorse be suitable? This tire is on sale for $272.99 a tire. My other consideration is the General Tire Grabber APT, 112 S, C. It is expensive though at $415.77 a tire. It’s also rated C, below what I am currently using.

I think I am having trouble because I use my 4Runner for too many different things. Any advice would really help! Thank you!