Some suggestions

* Use your hotel days for high intensity training, and your road days for distance.
* Rest days are as important as riding days. Particularly after HIT rides. Train hard, rest hard.
** This is the only point where your age actually matters
* Buy bike shorts. 3 pair. Just do it.
* Jerseys don't matter as much. Pockets are convenient.
* All rain is not the same. I live in the PNW, where rain is life. There's cold rain, light rain, intermittent rain, sunshine and rain, heavy rain, all day rain, all day and all night rain, days and days of rain, warm rain. So it depends.
* Certain things will make you unhappy: wet socks, wet head, wet butt, cold and wet body. Depending on the type of rain (see above) you want gear to prevent these.
* If you go with a rain jacket, you want a two-way zipper (so you can open up from the bottom) and pit zips.
** Friends don't let friends ride in the rain without pit zips.
* People outside the PNW mostly don't get this, but I'll say it anyway: Bikes ridden in the rain need fenders.
* When you get to the start line, you have the fitness you have. Ride within your fitness, and you'll be fine. Ride outside your fitness and you will be miserable.

Of course, stay on top of hydration and nutrition, but everyone knows that by now, right?

Do it, of course. No question.