I don't usually ride more than a hundred miles at a go, but if I did...
I would get a windshield, though the Scram's sweet spot is 50-60mph, and planning a trip using roads at similar speeds makes it more enjoyable.
Rhodie is right on with an Airhawk, though I always thought they were grossly overpriced.
Travel light!!! The Scrams biggest "weak point" is a lack of luggage capacity, but it wasn't really designed as a long distance tourer, so pack carefully.
Fuel. Get in the mode to stop every 100-120 miles for fuel (and your butt).
Other than that, if it's going to be mostly road travel, I think it would benefit from a more on-road tire set up.
Suspension mods would be nice, but if you are looking to save money, traveling light, frequent stops, and maybe an Airhawk pad and screen.
It seems like when I was younger all my friends would drive 1000's of miles on GPz550's, etc with a backpack and never complain.
All the farkling is for fun, and because we are all getting older!:w