In my opinion (and remember, you don't know me from Adam):
The America alternator is not the best around. Heated gear and extra lights (I have/use both) can bring charging down to about 12v even at cruise speeds. When using heated gear I turn off the extra lights when not needed (my decision when is 'not needed', you make your own).
Started with a Triumph touring screen, but replaced it with a large Clearview. I use Memphis Shade lowers, but take them off in the summer because I think it takes cooling air from the engine.
As far as seats, I've used stock, Triumph touring, beads, air pad, gel pad, and Corbin. I prefer the Corbin, but the advantage of the Touring seat is the ability to take if off with the pull of a lanyard, no tools. Very handy so I use it daily. If I could get the lanyard to mount on the Corbin, that would be the final decision for me.
A voltmeter is wired in (because of the one time I used too much voltage and was stranded in a snow storm).
Scottoiler.
A 3.5 gallon Tour-tank is plumbed in. That extends the range between gas stops. I have a bad back (it really does hurt most of the time, for what it's worth), but I find the America ergos almost soothing, so multiple 10-12 hour days are fine, your back is probably not the same.
A wired in Garmin Streetpilot III GPS on a Touratech mount. The screen is large enough to be seen, the buttons can be reasonably used with light gloves, it does turn-by-turn, and with an earphone plugged in will tell you how to get to a destination.
A Sirius satellite radio is mounted (but the longest trip so far, a 5500 miler from VA to Vegas and back was without any radio and that was fine).
Ear plugs every ride. They help keep the noise from wearing me down during hours on the bike.
Chatterbox wired in for a 3k mile trip thru Canada for the second time I rode with someone else (I prefer to ride alone).
Bellacorse saddlebag brackets and Tourmaster Cruiser II's after trashing a couple of sets of Saddlemen Drifters.
Always carried a bag of tools I never used (like insurance). Always carry a spare quart of gas that helped out 2 other bikers, I haven't used it yet.
I commute on my machine everyday and completed several Iron Butt rides (you're welcome to look it up) but I'm not a long distance expert. There are many books written on the subject (one multiple-around the world tourer, having ridden Indian, BWM/GS and assorted others speaks well of a KLR650 when going around the world, so does size matter?).
You can go as far as you want on any motorcycle that will hold together, if you choose to.
I really like riding.
