How to attached 6" mdf railing on loft bed?

The very altered loft bed I'm building for my daughter has an 6" tall 3/4" mdf railing that will attach to a 3/4" hardwood 'bed box' (8" tall all around, 2 sides secured to the wall studs). The railing does not run the full length of the bed but can attach to the footboard - though I put little faith into an mdf to mdf join. 

The footboard is also mdf and attaches to the wall by cleat, the 'bed box' and the ceiling so I'm not overly concerned about it being sturdy enough. 

I need help with some attachment systems. I don't know if pocket holes with coarse self-tapping screws but no glue for a clean face join is just inviting disaster. 

My other thought was adding some staggered vertical (alternating interior/exterior) braces - maybe 1x1s every 18" down the railing. 

 Any advice is much appreciated.