After catching my 7 yr old daughter standing on the Thetford to try to turn on the bath light... well... the light bulb went off!
Realized the bath wall is hollow. Drilled hole along top edge of wall and ran wire down to 1" hole for rocker switch (Radio Shack). Switch is 42" from floor. I wired an 1/8" mono audio jack in parallel with existing bath light switch and mounted beside fixture switch. This was toughest part. Velcro'd wire to ceiling. Now light turns on either at the door or above as before. No, it's not a 3-way! To stow pull plug from jack and let wire hang.
A mod that only your baby would deserve!
Troy