Near bishop? We are headed up there and was wondering how tight the dirt switchbacks are coming up from Bishop to get into the plain? From google earth they look a little tight and i'll have the trailer with us.
I've been up there several times. The switch backs are no worse than a lot of other offroad trails around California. Assuming it's an appropriate off road trailer, I don't think you'll have a problem. It's a fun and very scenic place, just don't expect a lot of difficult offroading.
You should be fine. We used to hike up there from the Glacier Lodge side years ago as well as drive over from Bishop. If our friends stock-height Ford dually can make it...