The Unity will limit where you can go, and if you can go, you will cringe a lot like driving many roads less than 16 feet wide with no shoulders. I'm sure Unity owners will disagree but you get used to what you drive and compensate in many ways. Heck, a large Class A owner will call you a wuss for this. Width of a C is just a nuisance. You guess correctly about the height. Over 10 feet introduces a lot of considerations. That is the real limit on the Going to the Sun Road in Glacier as there is a cliff overhang on the going west direction. The Needles Highway tunnels in the Black Hills will give you pause with 11 foot height limitations. The Daniel Boone National Forest 15 mile drive is nearly impossible with the narrow road (15'-7" measured in one spot) and its tunnel with anything other than a B. Those are just a few examples and I love to drive those kind of places.
As for tanks I usually go an average of four days between dumps. It is about a 5 to 10 minute operation. 10 if no one is waiting behind you and 5 if there is. As for showers I actually prefer the campground facilities. No RV is going to give you the luxury of a 3-5 minute full blast hot shower. If you want a shower in your B you are better off with a full service campground hookup as you can then not worry about dumping and you get better water pressure through your shower head with a city water hookup. The other debit with a B is most are wet baths with a couple of exceptions. You can let them drip dry or better squeegie or sponge them down a bit. Our shower curtain surrounds the shower area.
Most national parks have campgrounds that can accommodate any size RV. It is the national monuments (Natural Bridges in Utah comes to mind) and a lot of national forest campgrounds that are going to shut you out. Plus, a B can park in the oddball left over little sites or even in some tenting areas. Many a time I have lucked out that way. The last time was this month in Galveston, TX at a county RV park. The Class A in line ahead of me could not fit in the last site available. I could. Score on for the B team. :)
I understand the zoning for living. We have an electric tri-fold sofa that quickly converts to a bed with the touch of a switch. And we have two seats up front that turn around to a table. Still the sofa/bed is an either or situation and when the bed is down it feels like the B is constricted and it makes it difficult to get into the back cabinets. I don't like any of the current twin bed designs and see no need especially for the twin bed designs that act as opposing sofas. So, I am working on a design that will be unlike anything on the market today. A few DIYfers have done a better job in solving this than the commercial converters, IMO. Small Class Cs are not a lot better. They give you more width to feel less constricted but the slideouts are what really gives you space. But slideouts introduce a lot more give and takes if you really fancy the touring, stealth and go anywhere ideal.