I'm 6'2" tall, about 195 lbs.
I've been told not to go too big on a first bike several times, so I don't want to get into some 1000-16000cc beast that has more power than I know how to control. Heard several times that 600cc or bigger is plenty for solo highway travel at responsible speeds. That the little 250's "can" do it, but they're straining at 65mph for a real adult on board.
I'd prefer to stay away from Harleys since they have a bad mechanical reputation and are all pretention and little substance, nowadays. It's an extra $1000 to throw down the toilet, comparing a 883 or 1200 sportster to some of the other offerings from honda/yamaha/suzuki. And, I'd rather have water-cooled than air cooled. Not quite as "authentic" looking, but I've seen more than one harley stalled out here in the AZ summer, locked up at a long traffic light.
Honda's 745cc Shadow series is water-cooled, but the seat is only 25.9" from the ground, while the Yamaha air-cooled V-star 650 is 27.4" up. Suzuki's 805cc C50T is 27.6" from the ground and water cooled, but I don't like the look of that particular bike. Then again, an HD Dyna is 25.5-26.7 inches from the ground. I'm a tall guy and I'm sure I'd probably appreciate a slightly taller bike, coming to stops frequently. All 3 Asian cruisers are shaft driven rather than belt driven, and I hear that is MUCH lower maintenance than a belt.
For someone your size leg room will be an issue, seat height though isn't a hard and fast indicator of comfort though. You'll have to try it to see. As for the HD Dyna series they are a good choice for what you are looking, they'll do commuter duty just fine and will be good for weekend road trips.
As to Harley reliability/quality, the "reputation" in way out of date and really comes from the AMF period in the '70s. There is also the seeming need for a lot of HD owners to want to modify/customize their bikes. that sometimes lead to people that really have no business even owning motorcycle let alone having access to tools working on their own bike then not being happy with the results.
I've owned two HDs both of which have been rock solid reliable. I had over 80K miles on the first one before I sold it due to financial needs in '93. My current ride has just over 75K, a significant portion of that was my 100 mile a day commute. I did have to replace the cam chain tensioners at 50K but that design issue has been fixed.
I'm not one of those that dump on Japanese bikes, the big 4 make some decent machines but for the most part they just don't suit my sense of aesthetics. You mentioned the Suzuki C50T, I have some 1st hand experience with that bike, dad had one. It was physically bigger than my Road King, We found that out when I had to pick dad up with a flat tire, his C50 wouldn't fit on the same trailer he came and picked me up when I had a flat. I also thought it was under powered for it's weight/size. One thing I also noticed about it and a number of the other cruiser style Japanese bikes is the tendency to add large-ish bits of non-functional plastic trim for no apparent reason.
Two other makes I haven't seen mentioned are Victory and BMW. Victory makes some good solid bikes but their style doesn't suit my aesthetics either. I like some of the BMW machines and if I was in the market for a new bike today I would look hard at them.