Our 2011 Keystone Mountaineer 347THT is 12 feet 9 Inches plus we added the factory installed front AC. We've been from our home in Norman, Ok to Yellowstone and down to Las Vegas and back with absolutely no problems.
13' 4" and I do get "close" to the telephone lines on my street and have to move over on the back roads to miss overhanging tree limbs. If I see that big truck have hit them and see broken branches, I slow down and move over, my roof is not nearly as tough as a metal trailer corner. A few campsites have required a little angled entry to miss a tree limb or not backing ALL the way in. Our trailer is nearly flat all the way back with the loft in the back, so the rear is nearly 13' at the top of the back wall. Yeah, side winds really get us moving at 35' long and 13' high all the way back.
'05 Dodge 3500 SRW converted to DRW 4x4 QC LB SLT- CTD 325HP/610TQ w/ 6 speed manual- plus a little triple dog power...
'11 Crossroads Cruiser CF33LF- 35' triple slides, dual a/c's, LOFT over the rear BR
I will be nervous this year as well, we moved up to a new to us 5er that is 12'9, a little taller than the TT we were in last couple of years but will probably adjust. Definetly a good idea to put the height on the dash somewhere. Also like the rearview mirror idea...Genius