grahab:
So good to hear from you again after our meeting last October in Oklahoma City. Sorry so many places here would not accomodate your sweet little dog, but the dog is always welcome at our house (where it would just run around with our two little dogs).
For a "meet up" we need to consider air availability and climate. That's why I recommend Denver in September. Denver is an airline "hub" to which most of us can get a non-stop flight. Also, Colorado is beautiful then, with the aspen trees turning yellow in the foothills, and with a temperature in the 70's. It is also inexpensive to go and stay there in September, as it is not ski season or "summer get away" season.
So therefore, there is much to recommend Denver in September for the purposes of your post.
Thanks,
Richard :) :) :)