I have two comments regarding your proposal, first and no one has mentioned this but they are all over it when it comes to high resistance connection of the shore line to the campground pedestal. Connecting the cable to a hot outlet can and does causes arcing and should not be done. Install a disconnect between the outlet and the circuit breaker or install a switch type circuit breaker. Doing this allows you to hook up to your rig and then connect the power to the rig.
Second, most folks forget to consider the length of the run from the power panel to the outlet plus the length of the shoreline when calculating voltage drop. If you have a 100' shoreline and a 35' circuit, you have 135' of wire, not 100'. This may seen miniscule but remember that most outlets are loaded within 10'. Most RVs have 25' to 50' shoreline. In my garage it's just under 30' from the CB to the outlet and the rigs permanently attached 30amp shoreline is 25' and it I need about 45' of shoreline so I use a 25' extension for a total from the CB to the converter of 80'.
Is this a little complicated, sure it is but it is accurate.
