An S-10 should tow upwards of 5K lbs with no real issues......Of course assuming the 4.3 V6, not the 2.4L I4. The latter will pull 5K lbs, don't ask me how I know this, but you will not want to go very far, nor will you be fast!
Otherwise, if the price is right etc, should be a good boat, tow vehicle mix for your intent and purpose.
She drives me boat,
I drives me dinghy!