A friend in the US has a 2007 KLR and it's his 'loaner' bike when we've been over there (every couple of years pre Covid). I've ridden tarmac and dirt roads on it and it's ok. It's not great at anything but one of those bikes that's 75% at everything. Over here I have a Honda XR600 and a CCM 604 - both 600 singles. The Honda has a great engine (mostly) but the rest of it is much too minimal for travel - and believe me I've tried. The CCM has great peripherals - WP suspension, Brembo brakes etc (and you really can tell the difference) but the engine is, frankly, junk. The KLR is softer than the Honda and looser than the CCM (and heavier than both) but overall a far better package.

Re cruising speeds on trail bikes. You'll do well to find any sort of big single that'll top 80mph / 130kph when loaded up. Mostly the 600s do 160kph on the test track and 130 everywhere else. Plus aerodynamics starts making them feel a little unstable from about 120kph (those with high front mudguards anyway). They're at their best cruising in the 100 -110kph range. That's not Porsche on the autobahn territory. Given a choice I much prefer to use their engine characteristics on back roads - roads that are usually speed restricted either by posted limits or curves or surface. For me that's what travel by bike is about.