No much you can do about the marks on your hull. The super slippery stuff that people put on their trailers is great if you winch your boat on, like in salt water. If you do not strap the boat down really really well, it can slide all over the place.
Go to
www.overtons.com and type in "bunk". Tons of stuff will come. Replace the boards too with new ones. Use only stainless staples and galvanized bolts from the wood to the trailer.