I have no idea what's over there, so forgive me.
But, you sound exactly like me. I like to not only ride the socks off my bikes, but take them places too. Fatigue is the enemy when you're riding for a long time. 2 hours is a long time to ride, but I usually try to take a break every hour, even if its 2 minutes just to stop and breathe and stand for a second. But I can usually muster up to 8 hours in the saddle in one day if I stay on top of my human needs.
Get ear plugs, get a headsock, (they reduce noise and unwanted airflow) get comfy grips on the handlebars, and try to keep weight out of the backpack and either strapped to the bike or in a tank bag. Or just pack light. Tinted visor if it's sunny/glary where you are, and this one might sound weird, but I like tripping in my 1-piece suit. It's just the most well-engineered piece of riding equipment I have ever used. I don't care if I look funny, the leather is shaped to the riding position so you don't lose circulation (for me this happens in my knees with jeans) and the leather keeps the wind from battering you almost entirely, and with the right amount of under layers, you can stay extremely warm or cool, suits ventilate extremely well. A good compromise is leather riding pants.
Comfort is key! Point is, 2 hrs away isn't that far, but ease into the distance. I used to try to ride 1 hour on the freeway and back, then 1.5hrs and back, then 2 with stops, etc.
Hope this helps. Happy exploring!