Designing a semi-teardrop trailer and I have a few questions

Ok I really really don't know what I am doing so if your responses could be in layman's terms that would really help!
We want to build a cross between a teardrop trailer and a mini camper. It will be for both travel and a potential bug-out vehicle if needed. My husband and I both work from home so it would be great if we could have a space to work so we can travel and work. I want the galley on the inside and I want the ceiling a little higher than most teardrops which is what makes it a bit like a mini camper trailer cross over. I also want to great an 8" drop storage in the floor. Storage is important with this! We drive a car so keeping this as lightweight as possible is also important. I have a few questions that I am having a hard time finding answers to.
What do you use as the base? Thick treated plywood?
For the floor storage there will be braces every 2', how thick does the plywood covering it needs to be to keep from bowing?
I noticed a lot of people use luan plywood for the top. Is there another layer underneath that besides the braces? What needs to be done to make sure that is sturdy? It seems like just laying some bendy plywood over the top isn't going to work well.
What is the minimum thickness the plywood for the walls should be? We want to cut the frame out of one piece so we thought about getting 4 pieces of 4x8 plywood and glueing two over the other two crossway - would this work?
I am going to post my renderings so far! I should have curved the roof but going back and doing that now would be a pain. Let me know if you see any obvious flaws or improvements!
Thanks in advance!
We want to build a cross between a teardrop trailer and a mini camper. It will be for both travel and a potential bug-out vehicle if needed. My husband and I both work from home so it would be great if we could have a space to work so we can travel and work. I want the galley on the inside and I want the ceiling a little higher than most teardrops which is what makes it a bit like a mini camper trailer cross over. I also want to great an 8" drop storage in the floor. Storage is important with this! We drive a car so keeping this as lightweight as possible is also important. I have a few questions that I am having a hard time finding answers to.
What do you use as the base? Thick treated plywood?
For the floor storage there will be braces every 2', how thick does the plywood covering it needs to be to keep from bowing?
I noticed a lot of people use luan plywood for the top. Is there another layer underneath that besides the braces? What needs to be done to make sure that is sturdy? It seems like just laying some bendy plywood over the top isn't going to work well.
What is the minimum thickness the plywood for the walls should be? We want to cut the frame out of one piece so we thought about getting 4 pieces of 4x8 plywood and glueing two over the other two crossway - would this work?
I am going to post my renderings so far! I should have curved the roof but going back and doing that now would be a pain. Let me know if you see any obvious flaws or improvements!
Thanks in advance!