I have an 08 GSA and rode an RT1200 once. I like the RT. The GSA is very versatile can do anything. !00+ not a problem, no Tupperware so maintenance is easier. You won't have the wind protection, radio and cruise control that you do on the RT.
Check out eaglerider.com hot deals. They have GS GSAs for rent. Rent one and see for sure if you want it first. From your intro the RT is your bike. GSA does 70-80 mph on fire roads. That is a plus.
I thought most states will lock you up for 100+ mph riding.