"Villa Foam Core"  I still love it!

I thought I would have sold or dismantled this by now but I still really like it.

It is sagging a bit as you can see.

I'm thinking about re-building it in wood.

I've seen thin, lightweight, woods and particle boards and balsa wood strips for sale.

Is that what I would use to replace the sagging foam core structure?

FUN! Thanks for any advise you can give.