Re: leveling blocks
When I had my trailer, I needed the blocks probably 4 stops out of 5. Generally trailers don't have 'levelers' (for side to side, anyway) apparently because 'the frame is not strong enough'. What most do have are 'stabilizers' which cut down on trailer movement when you are set up.
So if your sites are level or not level front to back, you don't need them, but if the site is not level side to side, you will (and in my experiance, many sites are not level side to side). One of the reasons I went to the motorhome, messing with those blocks was a pain.