You grew up in it, so if its hard for you, think about how bad us snowbirds would do with it. The few times it makes 90's here a year, I don't find it to comfortable cruising on the highway. If I take the right back roads with lots of tree cover its not bad, but just out in the sun, I don't enjoy it. Fact in mid summer here I'm more apt to go out from about 6:00 PM on. I take a lot of bottled water with me in the saddle bags or make frequent stops where they have it. I just came in from a short ride over to my buddies house. Was able to ride in a T-shirt but on the way back, just about dusk, I could of put on my jacket and been more comfortable. Not humid at all here right now. Another month and that will change. I like riding in the evening when its humid. No jacket needed.
I think your ding very well doing 250 miles in a day. Couple that with the sun on ya, the wind ripping at you, being more alert etc. 250 is decent. In a car I like to do 400 to 450. I can still stay fresh each day. over that and I'm a sombie.... Bike, right now 200 I'm pushing myself beyond my comfort level... I could do it one day, but day after day would wear me down pretty fast. Dirt bikes its lots of riding but its all short runs, plus your up on your feet on dirt bikes, and you can sit it you want. My a$$ goes to sleep on the road bike, at least this one as it has the floor boards and they are forward instead of straight down like a dirt bike. So you can't stand up to get circulation in your butt again.
Bottom line, is your out there enjoying life.
Geo