Ok... I have quite a bit of experience towing a 27 ft Bristol hundreds of miles. So far, safely. I think you got a fantastic deal. Around here, you couldn't have bought the trailer for what you have paid. But, it is not "road" ready. yes, it needs something to keep it from moving forward. Also, as mentioned, lights. Then, an adequate tow vehicle. ...... a heavy duty 3/4 ton truck or more. If you don't have one, go rent from uhaul or similar. Next, make sure you have several heavy nylon straps (3 inch) with tensioners to tie the boat to the trailer. Then, have two more to tie the front and back support pads horizontally together. (like boat stands are set up with chain.... but use straps.... nicer to your boat than chain) Make sure you have safety triangles and maybe even highway flares to set out if things go bad.
Now, the most important part..... Find a route where you can go and never exceed 35 MPH. Also, make sure there are no low overpasses or bridges with low clearance. Have someone follow you with cell phones on speed dial so as to communicate any issues that they may see. Be ready to pull off to let traffic by if cars star to stack up behind you. It's only a hundred miles. Think of it like you are putting the boat in the lake 10 times. Remember..... take it slow!!!!! Take it slow!!!! And.... good luck!!!