Wall/floor/roof thickness

Building a 5'x8' Benroy on a northern tool trailer and am finishing up putting the trailer together.
I want to use a sandwich insulated construction for the walls with 3/4" plywood as the middle layer with cut outs for the insulation. I will be covering the teardrop in aluminum sheet.
With respect to the outer and inner skins for the walls, I am a little concerned about the total wall thickness when it comes to trim or when making a door or installing a manufactured door. I was thinking 1/4" on the outside and either 1/4" or 1/8" on the inside, so 1.25" or 1.125" total thickness plus the aluminum skin.
Is there a preferable standard wall thickness if you want to use the common aluminum trims or a manufactured door?
Floor will be 1by framing, 1/2" top, 1/4" bottom.
Roof will be 2x2 spars, 1/8" inside, 1/8" or 1/4" outside. I am not sure yet, 1/8" seems too thin but will 1/4" bend around the front?.
The floor and roof don't seem to be that critical, but I can see the wall thickness causing problems if common trims and doors won't fit.
Any guidance is appreciated. Thanks guys.
I want to use a sandwich insulated construction for the walls with 3/4" plywood as the middle layer with cut outs for the insulation. I will be covering the teardrop in aluminum sheet.
With respect to the outer and inner skins for the walls, I am a little concerned about the total wall thickness when it comes to trim or when making a door or installing a manufactured door. I was thinking 1/4" on the outside and either 1/4" or 1/8" on the inside, so 1.25" or 1.125" total thickness plus the aluminum skin.
Is there a preferable standard wall thickness if you want to use the common aluminum trims or a manufactured door?
Floor will be 1by framing, 1/2" top, 1/4" bottom.
Roof will be 2x2 spars, 1/8" inside, 1/8" or 1/4" outside. I am not sure yet, 1/8" seems too thin but will 1/4" bend around the front?.
The floor and roof don't seem to be that critical, but I can see the wall thickness causing problems if common trims and doors won't fit.
Any guidance is appreciated. Thanks guys.