I have thin calves, knobbly ankles and narrow feet and I have no complaints - but try them on rather than order them from a catalogue - they will likely be too tight if you order your usual size in them.
Oh yeah - they're snug at the top around the calf and they're alright for walking a couple of miles, although I wouldn't want to be pushing a bike that far in them.
I usually get brutal blisters from new boots, but these have been good, even on uneven ground out in the country. They are a little stiff at first, but they do wear in - easily enough movement to operate the shifter, even on a Guzzi.
If you're willing to go with leather, then Red Wing 980s - you can walk all day in those and they're lace ups so no worries with the calf thing.
I'm very happy with my Frey Daytona RoadStar GTX boots. They're armored in the right spots, comfy, and still watertight after 9 years. I faxed an outline of my feet to Helimot and they sent me a perfect-fitting pair of boots. These boots have a good amount of adjustment to tailor to your calf, and are available in narrow widths (wide ones, too).
I've found these boots perfectly comfortable for walking since day 1. But for nearly $400 I wanted to make damn sure I wore them out riding, not walking, so I keep a change of shoes at the office. Sadly the soles have finally worn bald. I've been trying on the Sidis and whatnot that the local shops stock, but haven't found anything I liked nearly as much. I may have to bite the bullet on another pair of RoadStars....
I use plain old everyday jump boots. You can get them in a plethora of sizes. They last a decade easily if you buy good ones. I'm on my third pair since I started using them in 1971. They last through a second re-soleing.
I have tried (and wear) most of what everybody has mentioned. I wear jump boots when I wear my uniform to work and I wear my "Combat touring" boots the rest of the time. I have a pair of SIDI tepor something (the expensive ones around $300). They are truely waterproof and a great product. I bought them a size too small so my son wears them now. The sole is soft & thin though, but there is armor galore.
Once you get used to the cinder block feel of the combat tourers and break them in (AND BREAK THEM IN), they work well. I, too, am rather thin. I like the concealed laces that cinch around my calf so they are as snug as I like. I can wear them under my pants or put my leathers down in them.
They are a substantial piece of equipment, sufficient for any a$$ kicking that needs to be done. Since they don't have any armor, I was hesitant on their ability to protect my feet. Well, they are really like a 1972 dirt bike boot that is tough and stiff. As a motorcycle instructor, I had a student mow me down with a Nighthawk. My tourer kept my ankle from getting broken (it stopped the bike), although the handlebar broke my wrist. Case closed on that thought. Oh, and the clasp on the side also helps in the fit. I put some good insoles in mine since I was in between sizes.
As I said earlier, the jumps boots work well, but are not as heavy duty as my tourers (but not as pricey either). On the other hand, they feel more like a work boot than an off road boot.
The best thing to do is to look around and find what works for you.
I dare say, I find an insufficient boot to be most bothersome. However, I rarely, if ever, stand in the back of my car, so I have no idea if the fit would be constrictive. The boot of my Austin 1800 will mostly likely accommodate several pairs of legs. I do find the working conditions under the bonnet in need of a good look. Best wishes in finding a suitable boot with which you may be able to tour most enjoyably. Ta-ta.