Andy, based on your questions, I assume you are very new to sailing and
boating.

Therefore, I suggest to you that it is very premature to actually buy a boat.
Most "4 berth cruisers" are very expensive to purchase and maintain, and very
time consuming, and you need to make sure that sailing is something you really
want to do before you take the plunge.

My recommendation is that you first make some acquaintances who are sailors
somehow and find a nearby location at some lake where people sail.

Get to know those folks, do some sailing on their boats, pick their brains for
the answers to your questions, and then re- assess your "dream".

Don't get me wrong, it's a wonderful, and achievable dream, but you need to
make sure that it's really your dream before you take the plunge.