Re: Good fit for 4?
I think the 17" works great for a family of 4.
We have a 17' Plan A. Two children - now 4 and 9. Works great and we tow it behind a loaded (with stuff) 2000 4Runner V6 - and, we pass other vehicles.
When our second child was born I slept in the trailer in the backyard because he was a noisey child and I needed the sleep for work. When we vacationed with him at age one, I slept beside the older one at one end while my wife nursed the youngest at the other end. Now the kids sleep at one end and we adults sleep at the other. Sometimes its musical beds.... Plenty of space and it tows easily although last year we invested in an equalizing hitch to stop the porpoising that sometimes occured while on bumpy roads. Its truely been our trailer for life.
Our biggest problem with the growing kids has been how to carry all the bikes, kites, soccer balls, lego, snorkels,...and enough milk.