I'd love to see different style and color of climbing vine on each section of highway barrier.
White climbing hydrangea,
Wisteria, there are many in many different colors.
I would mount some trellis as well to help them climb more easily, and to tie on.
Alot of the vines will do well in the shade as well, and it looks like you've got plenty of that.
I like Fast-Growing-Trees.com, almost everything is a rapid growth plant, and you can grow alot in a short time(Think 2-3 years instead of 5-15). I've got one of their "Royal Empress" trees, no joke it has grown 8 feet in 5 months. They also ship really quickly.
A fire pit is also always a good choice for getting people together even in cool weather.