First,
to the forum. There are lots of folks here with lots of experience.
Paying for the unit up front could pose a problem but not if you have a good, reputable dealer. Use the PDI from this forum when you go get it. Send them a copy prior to arrival so they know what the drill is going to be. Hopefully they are stand up folks that will take care of everything just as they should. Keep in mind that by the time you get it a month (at least) of your warranty period will have expired.
Everyone has a different take on extended warranties. Some would rather self insure, some buy the insurance and some do neither. Personally, I have it. Don't know if it's going to be worth it but I have it just the same. In your case, and the way you will use the trailer, I don't know if it would be worth it. A trailer being hauled/bounced all around the country traveling thousands of miles every year will encounter a lot of "stuff" that you won't being parked. Others will chime in I'm sure. Just take some time to think about all the different issues you think you may face, what would be covered under warrant, do a pro/con list and decide.
Congratulations on the purchase and good luck.