re: Any tips on taking a boat off the trailer on dry land????

The bow eye and transom eyes are lift points. If you have any friends that are truckers, borrow a couple of their tie-down straps. Get a come-along or a pully, connect the straps to your lift points and raise the boat a couple of inches (you could use chains instead of straps, but be careful to protect your gelcoat). Pull the trailer out from under the boat. You'll need to do this under an a-frame or a large tree (something you can put the boat under and connect your pully to).

Lower the boat onto some big blocks of styrofoam. A lot of outboards less than 150HP are packed in large blocks of styrofoam - check a boat dealer or two for some of their blocks. You may also have access to some old floating dock foam, like in the picture below. Basically set the boat on it's keel in the grass, or if on concrete, put a couple of layers of cardboard box down to protect the keel. The styrofoam blocks should be wedged on each side of the v-hull to keep the boat from rocking from one side or the other.

Repair your trailer, and reverse the process. Just keep in mind, you don't need to raise the boat more than an inch or two. Also, don't keep the boat hanging in the air while you make your repairs - the boat is heavy, and you don't want a kid or dog to play under it while you're inside getting a beer; shite happens.

If you are going to sell the rig, you might be better off repairing one side at a time and replacing with bolt-on supports. Place a couple of floor jacks on one side of the boat (one in front, one in back). Jack the boat up a couple of inches, cut off the bad supports, apply zinc-it, and then bolt on new supports.

ETA: most trouble-free and effort free: drop it in the water for a couple of days. This has the added benefit, it gives you a built-in two-fer boat ride scenario; once when you drop it off, and once when you pick it up. Make sure to bring extra beers for whoever lets you store the boat at their place for a few days.