Weight VS cost VS easy of build questions

OK I'm new here, and have construction questions.
First off, I would like to build a Standy TTT not a TD, on a 6x8 popup frame, and would like to keep the weight at, or under 1000lbs. (nothing fancy, just basic camper, no AC, fridge,water systems)some cabinets,bed etc. like I said basic shelter. I've built a lot of things with wood/plywood. So I understand that type of construction.
My questions are,
1 From the stand point of basic build cost (walls,floor,roof, etc)/ is there much if any difference in overall material cost ? How much differce ballpark ?
2 From the stand point of ease of construction (since I know wood) which would be easier (wood/plywood) or foam ?
3 From the stand point of weight (foam or wood/plywood) ballpark difference of weight savings of foam over wood.
This would be my first build. I know a guy that built a 5x8 TD. He is trying to sell it, because he wished he had built a standy. Trying to learn from him. And not wanting to make the same mistakes.
All input very welcome. Thanks
First off, I would like to build a Standy TTT not a TD, on a 6x8 popup frame, and would like to keep the weight at, or under 1000lbs. (nothing fancy, just basic camper, no AC, fridge,water systems)some cabinets,bed etc. like I said basic shelter. I've built a lot of things with wood/plywood. So I understand that type of construction.
My questions are,
1 From the stand point of basic build cost (walls,floor,roof, etc)/ is there much if any difference in overall material cost ? How much differce ballpark ?
2 From the stand point of ease of construction (since I know wood) which would be easier (wood/plywood) or foam ?
3 From the stand point of weight (foam or wood/plywood) ballpark difference of weight savings of foam over wood.
This would be my first build. I know a guy that built a 5x8 TD. He is trying to sell it, because he wished he had built a standy. Trying to learn from him. And not wanting to make the same mistakes.
All input very welcome. Thanks