Small sailboat, for a few thousand bucks? May be becoming a blow boater?

Looking to train a son in sailing, and want something challenging enough we won't outgrow too fast. Still has to be trailerable less than 2K pounds, 15 to 17 feet, or so, a centerboard, with a spinaker, trailerable, with more than a footwell, for two, maybe 3. So Laser, Sunfishes to small but saw Boston Whaler 4.3. and 5.2, hard chine looked dry, lot of space, good daysailer. small 2hp kicker Any suggestions