How to avoid having a ladder in your tiny house
I suggest that you make a list of what you want and another list of what you need. There are several lists and guidelines out there that are free. There are free planning software options as well. The biggest challenge is to keep everything to scale. People tend to draw couches and beds into their plans when in reality, they have drawn their queen pull out hide-a-bed all of 3 feet wide.
Next be aware of your budget. To house a family of 5, you may consider a large rig that can pull a heavier trailer. Everyone will need some time out space! A triple axle trailer is probably a good option for you.
You will require a bit more kitchen than a couple would need. Full stove and fridge. I found a great 5 burner range and oven that will fit easily and will be handy for canning.
As far as bathrooms, having an ADDITIONALOUTDOOR SHOWER and even a camping toilet for emergency issues would be very inexpensive. We actually were contacted by a woman that wanted a 20 ft trailer with 2 bedroom plus a guest room with a guest bathroom! (I wanna know what she was smokin’.) Remember, if the THOW is to be mobile and go anywhere in the USA, 13’6″ is the tallest it can be. 8’6″ is the widest it can be.
As you have read, some people could care less about proper building and some build to code. Personally, building to code is the way to go in my opinion. The industry is maturing and communities are sprouting up. That means new zoning laws will happen and new building regulations will be established. Who knows if they will allow owners of non-compliant homes to join a community.
Depending on where you are located, see if you have any home shows that feature THOWs or any builders in your area. Most of us that build custom THOWs do not maintain an inventory to show. (Our are usually sold by the time it is completed.)