Once put together, this thing is pretty solidly constructed yet not heavy. It came with a LOT of pieces, but don’t be overwhelmed. It was probably the easiest piece furniture from Wayfair that I have ever assembled. We purchased the Signature Sleep 8” gel mattress for the trundle which will be perfect. It’s plenty of cushion and still leaves some room for sheets, blankets, comforter, and even a pillow. For the main bed, we are using a spare 12-13 inch mattress we had which is probably a bit too high, but still works fine. The trundle slides in and out quite easily and the wheels can lock in place during use.