I have towed my son (now 5, we started when he was 3) over 1000 miles, on two different tag alongs. First was a non-pedaling version of the Instep Hitchhiker. We really liked it, it towed well on the road, but was only mediocre on singletrack because it doesn't have enough clearance over the rear wheel. This year, we've put almost 500 miles on an Adams Trail-a-Bike. After extensive review and comparison we settled on this model mainly because: 1) it is excellent offroad (lot's of rear tire clearance so when I go over steep hills (small, steep hills where there isn't a flat surface at the top but immediately goes back down) the arm attaching to my seatpost doesn't rub on my rear tire 2) I have multiple hitches so I can tow it using any bike I own; btw, the hitches are $15 through REI, $30 everywhere else) 3) the construction of the frame protects the front chainring.