HW, I see a few guys with the quad door up front on trailers so it must be a pretty popular option. Figured you'd want the cows up front so there'd be more weight on the pickup but it must not be too big of a deal.
IB, 90% of our trailer miles are highway or gravel. It's that other 10% that has me worried!
If you are truly hitting 90% highway miles, I'd get a Wilson. A Wilson can handle ranch roads and gravel alright. Just ease up a bit when you are on those surfaces.
I sold our steel trailer about 6 months ago and bought a 22' used Wilson and haven't regretted it in the least.
As to slam gates, you can order them. I don't believe they are standard. I worried a bit about that but have found I get along pretty well with the conventional latch on the rear gate. Our middle gate has a slam latch and it's handy.
