Something else to consider would be some of the better inflatable catamarans (minicat, smartkat, ducky). The problem is that you can't find them used very often and new ones cost much more than $1,500.
They go together fairly quickly, are fast, and you can't beat the portability. I own a SmartKat and it packs up into 2 six foot long bags that weight about 50 lbs each. It can easily go on the roof of a car. My main complaint is that it doesn't point very high and it can be a challenge to tack in some conditions. Other cats have these problems as well though. I was able to find one on Ebay last spring. There is a dealer in North Carolina but they are much more popular in Europe.
The larger Minicat and the SmartKat claim to have a capacity of 4 adults but in my experience it's not practical to sail a SmartKat with that many bodies on board. Two adults and a well behaved dog are probably OK.
Ducky's are available in a variety of sizes and I'm sure you can get them in a size large enough for your needs but again it's going to be big $$$$.
What might be a better option still is to find a sailing club in your area. You don't have to worry about transporting or storing a boat (you use theirs) and some of them at least will help you learn to sail.