When you say you're only going to use the lock when you're at a cafe, are going to be in sight of the bike at all times? And is that the only places you will be locking up the bike? if so a D lock is heavy and bulky but they are the best, problem is for locking up something with such a solid of a lock that you're going to be keeping an eye on it most of the time seems a bit of an overkill to me especially being in a rural area.
There's two ways of looking at this. The way I look at it is I just have a stupidly simple cable lock, it's enough of a lock to keep honest people honest, but if someone tries to cut it I'm never out of sight of the bike long enough for that to happen unnoticed, and since where I live bike theft is a rarity I'm not concerned, in fact I lock my bike outside of my work with that same lock for years and I have no fear about it, and I use it in my garage to lock my bike, and I use it on when I go bicycle camping and lock the bike with it to a park bench while I sleep. If using a cable lock scares you, fine I understand, and if I were in your shoes with that sort of fear then I would at least find a lightweight alternative like this TiGr mini lock:
View: https://www.amazon.com/dp/B0155L1G9W?tag=thbebilo-20&linkCode=ogi&th=1&psc=1
this lock weighs less than a pound whereas a D lock can weigh more than 3 pounds like that Abus Granite D lock, and the TiGr lock works similar to a D lock. 3 pounds is a lot of weight to carry around for something that you're only going to use it at cafes while on long rides, I don't even bring my lock on long rides where I know I'll be stopping at some cafe.
With that TiGr lock you could carry a looped cable you can buy at any home improvement place and wrap the cable around more of the bike and loop it through the TiGr lock, I don't see why you would want to do that but just a thought if you want a bit more security.
Anyway just a different thought to consider.
There are a couple of really lightweight locks like the OttoLock Cinch, these are useless, they're nothing more than a thick lockable zip tie and there have been reports of these locks being defeated in less than a couple of seconds. If the cost of the TiGr lock is a bit high for your budget than consider the Foldylock, it cost the same as the Abus Granite D lock but weighs a pound less, see:
View: https://www.amazon.com/dp/B0753FDJG8/?linkCode=xm2&tag=popularmechanics_auto-append-20&ascsubtag=[artid|10060.g.3032[src|[ch|[lt|
The problem with the locks like the Abus, and the TiGr is that they take up a water bottle mount, which means you have to carry one less bottle of water with you unless you throw them into a backpack, the Foldylock comes with it's own mounting system that doesn't require a water bottle mount. Another lock you can get is one that you wear around your waist, though this lock is as heavy as the Abus lock but it's cheaper than the Abus, is the Hiplok, see:
View: https://www.amazon.com/dp/B007FNX4I0/?linkCode=xm2&tag=popularmechanics_auto-append-20&ascsubtag=%5Bartid%7C10060.g.3032%5Bsrc%7C%5Bch%7C%5Blt%7C&th=1
That Hiplok is quite long, longer than a D lock making it easier to wrap the lock around a pole, but you do have to wear it around your waist. I do have a problem wearing something hard anywhere near my body, if you have an accident that thing could do some serious damage, if you want examples of damage stuff did in accidents just ask and I'll spend the time to tell you.