The 4.7 tows ok on the 4runner. The v8 is awd, the v6 is rear. I've towed single and dual axle trailers, the duals pull so much easier even on a 21ft skeeter compared to my single axle 19ft. With your boat, it should be a cake walk with the 4.7. The 4runners off road capability and drivetrain is great. I trailblaze on the lakes and wouldn't want to be in any other vehicle than the v8 4runner. Get on the lake, lock the center diff and give'r.
If I was to buy a newer suv, i'd probably look at the current Lexus GX460 and skip out on the current 4runner. The GX sports the current V8 4.6 with AWD. Good Luck!!!
Lexus? Man, one must win the lottery to purchase such name brand....Also, with that SUV....I wouldn't want to go offroad with it--too pretty!! Interesting though. A guy in my neighborhood hauls a 22' ski boat with that gx460. GO YOTA!!
I currently pull with my 4.0L Explorer. A few things I don't like about the explorer is its car base frame, big fat axle arm joints. I get stuck in 10" of snow/mud b/c low clearance. Its a little slow at acceleration and inclines. Other than those few things I love it, hauls ok for the northern states here, passengers enjoy the DVD, leather seats and 3rd row seating.
Dual axles are awesome! Makes towing much easier.