If the deck is not too high where the Tanzer is I would get the two guys (or borrow some more weight) to heel the boat so you can see what the bottom is like. Generally the part just below the waterline will be the worst. If the owner will let you, scrape away the crap down to the glass in a small area (4" by 4") to see what you can see. My sense is that blisters are likely to happen in the first ten years or so and both of these boats are older so it should not be a big issue.
One boat has a trailer and the other not? If so, you have to figure out how to get the other one home if you go that route. Someone mentioned prices - New England to Chesapeake prices tend to be higher than further south, but the boats are out of the water for a good part of the year so they are 'newer' in a sense. Also I get a sense that people in the NE tend to keep their boats in pretty good shape.
Before you get to far with these boats find out what sails there are and the condition. You probably will not be able to tell much about the shape but you would be able to see if they are in good shape physically.
Back to Grenada in early December. Not sure I will remember how to sail. Will spend the winter and early spring in the Caribbean and then head to Bermuda and the northeast US. Still trying to decide if we will bring the boat to Canada, either in 2015 or 2016.