congrat's on the trailer... looks like you should be towing that just fine. I wouldn't worry about the alternator, just add a 2nd battery if you don't have one and plug it in the night before a trip. As far as the X you're getting the right equipment for towing. You probably will want to get a tranny cooler and maybe even a temp gauge for those long pulls up the sierra's.
We'll have to get together this summer and go do a trip here at cisco grove.

It's a mile up from the eagle lakes trail and right at the middle exit of fordyce trail... real nice place.