CloudDriver's advice is best. I do this ~100,000 miles. My pan was last dropped around 170k, and now I just do the pump and fill method, and also use an inline Magnefine filter. Fancy fluid isn't necessary. Anything meeting Mercon-V spec is good fluid, even the parts store stuff. I use Napa because it costs under $4/qt.
I'll hit 420,000 miles this weekend. Over half those are towing miles, and my combined weight is typically 20-22,000 pounds, with lots steep, rugged forest roads. Sometimes with two trailers in tow!
