Those sound like good ideas. A few, pre-measured almonds? What about a small amount of whole milk for the chocolate milk, just to get that rich smoothness & fat, but in a small amount?
Or, maybe some kind of packaged drink that also has a good helping of soluble fibre with its protein? Wonder if that might help fill you up until you got home?
Don't do what I did all spring and summer. I managed to not lose one pound, and even gain some, even doing 80 mile training rides up to 8,000 feet of climbing, in the rain. It SEEMED like I should have earned a whole pizza every Saturday after my long ride...
Speaking from experience, it is possible to gain weight, even doing long, hard workouts, including distance and intervals, eating the wrong things.
Good luck!
"The best rides are the ones where you bite off much more than you can chew, and live through it." ~ Doug Bradbury