I ride a scrambler as an only bike (there's a Tw200 in the garage, but it belongs to the Mrs.). One of these days 'll convince her to sell the TW that she rarely rides, and I'll have space for 2 bikes again. In the meantime, for a one bike scenario, it's really hard to beat the Scrambler for the riding you describe. My riding is around town errands, 1-200 mile weekend jaunts, and lots of county/gravel/forest service roads.
You'll miss the Tiger on the longer trips, but it sounds like that's not very often. Occasionally I'll take a longish trip, and the lack of wind protection starts to bother me at high speeds. So then I begin to lust after a Tiger 800 to replace the Scrambler. The 800 is way more bike (and more money) but eventually I come back to my senses. I'm just not ready to give up the admittedly hard to quantify "style" enjoyment of the Scrambler. It's more fun to look at, tinker with, and customize. And the lower seat height is a little easier to live with around town. It's also just a little more fun to ride in the sub 80 mph range.
Good luck. Honestly, I think it sounds like an awesome plan for Father and Son Scramblers! I certainly wish I could get my dad off his 1300cc cruiser. 2 scramblers could have some serious fun exploring together. Good luck.