Being a bit dim here maybe but?
The chunder ace has got to be up there as a sports tourer these days. Anything sporty come modern will be harder and less supple than the ace.
I think your looking for what you have, unless you feel like going chrome, the BEST distance riding i did round Derbyshire a few years back was on my dads Suzuki intruder.
Miles and miles, straight back, comfy seat it just eat the miles. I wasn't breaking into hairpins but i could have rode from dawn till dusk without trouble. No silly crap on it like noisy exhausts etc, just a stock 750 V twin. Shocking front brake and shite in corners but it was comfy.
Or go old, FJ will take some beating as a mile eater, or one of the old gs shafties. 5k gives you a lot of choice, i would ignore the newer stuff.
But hey, i have been known to do over 700 miles in a weekend on my TDR 250, probably THE most non distance bike in creation. Yes i was hurting afterwards.