I was going to put a response together for you yesterday, but got sidetracked, so here goes.
Years back, my dad and I bought a Yanmar with a 48" RFM. I did a lot of mowing on a 2 acre Connecticut lot, with boulders, trees, dips, slopes, flat areas, and all sorts of typical New England obstacles. I wasn't a big fan of the rear finish mower - lots of stops, backing, turning, and other time consuming maneuvers - it did shine backing up to mow under trees, but as far as I was concerned, it was a cumbersome mowing setup.
My most recent machine had a 60" MMM, and it was a much easier machine to mow with. One of the big improvements was that with a MMM, only the front wheels ride ahead of the mower - 4 wheels, especially the larger rears rolling over the grass ahead of the RFM, trample a lot of grass and leave a lesser quality cut on the lawn.
Between both of those machines, and with my last couple of years doing some major landscaping, I decided that when I purchase a larger machine , I will not purchase a mower deck for the tractor. Instead, I would opt for a nice walk behind 36"-48" dedicated mower (you can get seat or platform trailers so that the machine is pulling you around, instead of you running behind it), or a zero turn riding unit.
It just got to be a bit of a pain having to remove all the dirt working attachments and put the mower on just to do an hour or two mowing job, then go back and switch everything out again. I had a lot of landscaping tasks for a 2 year period, and it would have been nice to not have had to do the mowing with the tractor. Another issue is that even a 5' wide finish mower can be a pain if you are not on a completely level lot - it did a beautiful job, but on the rolling ground, even a 48" walk-behind can have difficulty doing a nice even cut. For something the size of a
B3030, you'd want the 72" MMM so that you can get in close to trees, shrubs, edges, etc., and assuming you've got some rolling land up there, you'll be doing touch-up with a walk behind.
Sounds like with the limited amount of manicured lawn, a mower deck for a tractor of that size might be a bit overkill, plus you don't want to beat on a finish mower deck mowing field grasses. If you have more field grasses than manicured turf, a 3pt mounted rough mower will do fine, even attached to a
B26, and if you wanted to lighten the front a tad, you can drop the bucket off the QA.
Since I sold my tractor, although I miss that nice 60" MMM, I've had the use of a 37" walk behind mower, and I must say I'm really impressed with the cut, and I am getting my exercise. Once we've chosen our next property, which will be larger than the current one, if there is enough manicured lawn to justify a decent mower, I will be getting a tractor for the landscape work, and a separate dedicated mower to deal with the lawn. If I didn't have a need for so much landscaping work, I might have a different opinion regarding the tractor mounted mower. But I like my landscaping projects, and with a tractor, I find myself planning new projects every year.