Here you'd have to buy the insurance for a year. When you sell the bike ... you get a refund on the unused boit of the insurance ... minus costs.
As some one said - get an international drivers permit .. then you will not need to get a local licence in the USA.
For the documents .. if they are going to take a while .. and you probably want to ride away .. have the documents sent on to you (give several addresses at different times .. say a week apart) AND do take copies of reciepts just in case someone askes!
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S