insulation is a good thing. Condensation is a problem of lack of ventilation as well. Keeping air moving helps this A LOT but insulation is required to keep inner wall warmer than outer wall. But jury is out on how much it matters for the floor since the most have a mattress providing insulation.
My big plus of insulation is noise reduction. Helpful when you camp in a campground.
As others have said, your plan is WAY WAY overbuilding that teardrop. If your going that route I hope you have something big enough to effectively tow it. There is absolutely no need to be built that heavy.
My first build that was way over built was 2x2 framing (some 2x4s used in certain places) with XPS foam filling all voids, 1/4" ply external, 1/8 internal with PMF outer coating. 1400lbs loaded for the weekend. And that shell was about bomb proof.
One I'm doing modifications to a trailer now for will be lucky to weigh 500lbs empty if I have my way and most of that will be the trailer itself.
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