I've done several 3 day - 1000mi.+ rides on my Vulcan. I personally don't have much of an issue with the stock seat, but I was on dirtbikes a lot longer than the Vulcan, so I'm kinda used to an uncomfortable seat.
On one of my longer rides, I used an external framed backpack mounted on the rear rack for most of my lighter luggage (ya want to try to keep the center of gravity nearest the center of the bike as ya can). The heavier stuff went in the saddlebags (keeping the weight low on the bike is also a good idea)
I did one of those rides with the PlexyIII shield. It took some getting used to, but it never had me feeling too uncomfortable if a gust caught me. Just gotta remember to ALWAYS
pay attention while riding. Sure, the view may be spectacular, but there not much to view from a recovery bed if something catches ya totally off guard! If you want a good look, pull over, experience the view, then ride on.
And, don't forget, controlling a bigger/heavier bike that will still get some effects from wind could wear you out faster/easier than having to control a lighter bike.
Experience plays a big roll in knowing what the bike will do in certain situations (such as wind gusts). Like Curtis said, get used to really long rides a little bit at a time, don't rush it all at once if you haven't already done rides atleast 1/2 as long as what you expect to do for visiting your daugher.
I have stock handle bars. I'm about 5'7" and have them mounted just about parallel to the forks and that works good for me.
There may be some "universal" fairings you could make fit with some creative engineering, but there was one made specifically for the 750 Vulcan, but they're usually hard to come by and go for near top dollar when they are offered for sale. But some people have got lucky and found them cheap.
The limited mileage didn't bother me or my riding buddy much, seeing as we both smoke, so the fuel stops were kinda looked forward to.
Some kind of highway bars would be a good idea. More than a few types have been made by bike owners themselves, out of easy to acquire parts and pieces. Just need some minor mechanical skills and it's not to hard to come up with something that'll work. (just be sure they're mounted securely!!)
And, one requirment for sharing all this personal experiance.....
....TAKE A CAMERA!!! We want ride pics!!
And good luck to your daughter at school!!