As Reggie described there is a large luggage rack on the lower level for big pieces like your backpack and guitar case. There is also a hanger rod (or a skinny closet) in the room for garment bags and such.Now you will probably think I was crazy, but on my last trip on a Superliner Standard Bedroom I actually measured the space under the seats with a little tape measure on my keyring. (Get a life, Mr. Toy!)
The space under each seat is....
9½” tall
23½” wide
26” deep
If your small bags are no more than 9" thick they will easily fit under the seats.
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Trust God, love your neighbor, and never mistake opinion for truth.
-Mr. Toy