Absolutely love my TTR - it is my do "everything" bike - but first and foremost it is my daily commuter in the Cape Town traffic that is just getting progressively worse. A job it does absolutely admirably being nimble and light. Secondly it is my weekend warrior, from playing in the sand to weekend trips (which do not happen too often unfortunately).
I am happy admitting that it is going to fall short on something trying to make it my "jack of all trades" (or possibly many things in other people's opinions), but what the TTR will fall short on is:
"Most miles will be tar and quite a bit of that will involve at least some stretches of highway, so cruising at 110-115kph should be comfortable for both me and the bike."
You can definitely push it up to sit and cruise at 110, but not having a tacho, and thus not knowing what revs the bike is doing at 110 / 115 - not sure what the long term implications might be of doing that from a reliability point of view. And fuel economy takes a big hit sitting at 110 / 115 for sustained periods. For cruising I find that it is best kept at 100 for fuel economy to not take such a drop - and just for my own peace of mind for long term reliability. I run a 48 back sprocket BTW, stock front.
The DR350 is as scarce as hen's teeth off course, know of a few people waiting for one to appear on the market. So options are limited, unless you include the DRZ400 into the list?!