Well, for starters, you'll need to install a disconnecting means within 30 feet of the mobile home 550.32(A). At this disconnect, you will need 2 more ground rods in addition to the two at the meter pole.
Unless you are dealing with a really old mobile home, the neutrals & equipment grounds will already be separated & waitng for that 4 wire feeder.
I don't believe that URD will be in compliance. You must pick a conductor or cable from table 310.3 Try looking into USE-2 , most brands that I've seen are also listed as RHW.
Take a look at all of Article 550, especially section III.
Tom
