As to "parkways", I always assume trailers are not allowed, unless I know specifically otherwise.
You are correct if a road is called a parkway do not travel it, not because of the hefty ticket you will receive but some parkways have low clearance for the overpasses.
I tow with a 04 Excursion V-10. I have 373 gears, but I believe there was an option for a different gear ratio that would push the tow limit to 11,000lbs. I suggest looking real hard at the gas excursions, they will be cheaper to buy and you will not need to bullet proof them.
In my front pass through storage I placed some hooks that I simply slide my wd bars onto and leave them there until I need to hitch up again, this way they can be secured as well as kept out of the weather and off the ground.
My 2004 V10 Ex has taken us from Florida to Maine without issue. I did add a rear sway bar that was beefier than the factory one. My TT weighs around 9200lbs when loaded to camp. I do have E rated tires and installed new shocks when I bought it in 2009. I opted for the Roadmaster Active Suspansion to shore up the Ex's soft rear instead of airbags. I mainly use the Ex to tow and average 7.5 - 8 MPG.
I would go with 1200lb - 1400lb bars.
I have a 2010 Jayco 32BHDS. The outside kitchen was not available in 2009 when I ordered the TT. The bunk house has 2 upper bunks and 2 Jay Cubes to sleep 4.It also has an exterior door to the bathroom.