Here's my 2 cents on your questions 2-4.
2. You won't have any trouble stopping your 3000 lb boat without trailer brakes as long as you drive as though your stopping distance will be much longer, because it will. Legality will depend on your state. Very generally speaking, brakes are required on trailers over 3000 pounds. Some states use a percentage of vehicle weight and some use performance standards.
3. I seriously doubt the police will bother you based on the physical height of your boat (guessing it's a sailboat)? as long as you are driving sanely and not having any obvious control issues.
4. Your TB should not have any problems pulling a boat up a ramp, in fact it might do a little better than some of your buddies pickups due to better weight distribution.
You mentioned that your previous tow vehicle was an Astro? An Astro van weighs far less than the 7100 pounds your stated in your first post. Your TB should pull that boat much better than an Astro.
