...I want to sail from Boston to Florida... If I have the boat and it is seaworthy, what can I expect...Iam sometimes impulsive, but I wont quit if things get tough?
I would expect you would be uncomfortable, wet, bored, thrilled and elated at various times. That is a long trip for a newbie, sort of like a casual walker deciding to hike the entire Appalachian Trail without ever having been camping. Even though you might imagine sailing most of the way, you will probably spend quite a bit of time motoring, or waiting for the wind.
Why do you want to do this? Sailing is great, as is camping on the boat while you travel to and from a nice destination, but living on the boat while you travel down the coast for weeks and weeks on end in all kinds of weather? People (delivery captains) are paid to do this because boat owners do not want to. Beware of undertaking an activity that will cost you money when others are paid to perform that same activity. That should tell you something.
Personally, I enjoy day sails, weekend cruises and extended cruises up to about 10 days. After a week, I long for air conditioning, a dry stable bed, and an easy and convenient lifestyle.
Essentially, at your price range, you will be on a very long, uncomfortable, camping trip on the water.
You should ease into sailboat cruising gradually. See how you feel after a weekend aboard or a week aboard. You might change your mind. I would try to invest as little of your own money as possible before committing to the boat purchase solely for the purpose of taking this extended coastal trip. I second the recommendation to crew on other people's boats while you learn the ropes.
By taking it slow and trying some shorter cruises before you commit to this trip, you will also discover the answer to your own question about how much experience you need. Like any other activity, although anyone could learn to sail and cruise, extended cruising will be easiest for those with a certain skill set, natural ability and personality. You will not need as much experience if you have great natural spatial relations ability, good mechanical ability, some athleticism, problem-solving ability, a calm and decisive temperament, courage, perseverance, independence, self-reliance, introversion (if you sail solo) and a love of nature. While you could force yourself to finish the trip without any strengths in this particular skill set, you would probably be miserable and may meet with some mishap, such as the loss of your life or your boat.
Staying a mile offshore would subject you to an unnecessarily long, winding and dangerous course. Most of the hazards are closer to shore. Plus, you want to take the shortest distance possible and the coast is not a straight line. Even coastal cruising, you will likely be from 5 to 25 miles off the coast.