X3 on the hook and eyelet solution. We've done that to all our RVs, even though now our children are old enough, its not really necessary.
My BIL and his family just bought a new 5th wheel, he has smaller children where this is an issue. Last week, I helped him install the hook and eyelet. 'Tis the perfect solution - if you mount the hook/eyelet just above the sliding piece, its very easy to latch or unlatch from inside or out, yet its high enough a toddler can't reach it to unlatch it.
Oh, and the previous poster, that suggested a toddler falling out the front door would not do much injury/damage - WRONG. Some camping friends of ours had that happen a few years ago to their child, and a trip to the emergency room of the hospital was the result. You do NOT want them pushing that door open and falling out unintentionally.
