I will look at Experience Plus, Tulip.
I know that all of France is on vacation in August, but since both of the France options are supported tours, with very experienced companies, I am pretty sure they plan their tours accordingly. The places where you stay on the France trip with Backroads are outstanding, and to me probably worth the price. They run this trip every week in August, so apparently, some places are open! Our friends did a bike across Italy trip with Ciclismo, before we knew them, and they were very happy with the trip, except for the horrible heat, which none of us are willing to put up wit at this point. Riding in southern Spain at the end of May almost killed me, and I swear if I hadn't lived in a desert climate for half my adult life, I would have been in the van the whole time. As half of our group was from Australia, they were used to it, but I kept thinking that if I was a typical person from the northeast, riding temperatures around 100 would have been shocking. So, weather is also influencing my decisions. Ireland is cool, but after 5 days of riding in the rain in the Finger Lakes, last year, I hesitate to go anyplace where there is a high probability of rain.
I know this sounds picky, but these trips are vacations for me, not so much "training opportunities." Except for my trip to Spain, I didn't really do any special training, and that was only because it was so early in the season. I tend to just push through, grin and bear it, as I know I can get through horrible climbs based on what I do at home. I may be slow, but I can do it. The only reason I didn't do some of the "extra" climbs in Spain was the fact I was on a rental bike where I could not reach the brakes from the drops and the lowest cog was a 25, as opposed to the 27/28 I have on my carbon roadie.
This is somewhat of a digression, but over the years I have learned a lot about myself on these trips. Each one had its plusses and minuses. Spain was definitely the best, due to the small, international group, and the leaders, who are the actual owners of the company. The riding was horrifically hard (we did 2 climbs that were on a Vuelta route), but the other parts, especially the food, made up for it. The trip to the Finger Lakes was the worst, mostly due to the weather, but I also found the scenery to not be that wonderful, coming from eastern Massachusetts, and we were riding on roads with wide shoulders, but filled with debris. I had 5 flats on that trip, and 2 more when I got home, when I finally bought new tires.
A lot to think about.