3. We have two memory foam mattresses. One is 2" and one is 1 1/2". Bought from Target.
4. We put down the table and store them on top when traveling.
My wife would agree with you about the stock mattresses. I'm actually ok with them, but I admit the memory foams are really nice. Not that you asked, but the heat gets through the foam just fine if you turn on the heated mattress a couple hours before bed.
DW, 3 Kids and our Goldens
2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD