You need to empty the water out of the tanks (obviously), down to just above the gravel... if you keep the gravel wet, the bacteria will stay in it and you won't have a new cycle. Also keep the filter material wet. Always transport a tank flat on it's bottom, or the different stress can crack it (not sure this matters as much with acrylic).
You can just bag the fish and they should travel well. Since they'll be out for a while during you setting the tank back up, you probably want to put them in a cooler or styrofoam shipping container to keep them warmer. With the big fish, you can even use a clean trash bag inside a bucket (like a 5g bucket or a kitty litter bucket), tied of course... you might be able to move all the 70g fish inside the same bucket.