All you need to buy is a 50 amp Smart Surge protector from Progressive. It is 240/50 amps, provides 1650 Joules, and protects up to 45000 surge current. It also is polarity tester. Like Pianotuna pointed out, THAT is very important before you connect your coach cord to shore power.
I have had a couple of instances where it has shown that where I was going to connect it was wired wrong. But the Smart Surge protector from Progressive has warned me about how the shore power was wired and a couple of red led lights will light right up.
They usually cost around $140, but you can find some places where you can buy them for around $124.
That is all you need.
You can spend hundreds of dollars for a hard wired set up, but it is not really necessary. OVERKILL!