Our MH is 12' 10" high, so you just need to really watch and pay attention. You are OK on any of the major freeways/interstates ect. For the most part anytime you see big rigs taking the roads you will be ok in height. The big rigs on a regulary traveled route tend to naturally keep the trees higher than your MH(even though they look close). If anything hits it would be the flimsy type branches/leaves and will not do any damage.
The real problem comes in some of the CG's and on side roads that the big rigs don't travel. We have had to back out of some places due to low hanging trees. We just pulled into a State Park where the ranger said they had plenty of open sites, but wasn't sure we could fit length wise. When we pulled in there were several good spots we could fit in length wise, just all the trees were too low in the spots as well as the access roads. When I spoke to the Ranger he said he never even thought about height being a problem.
Also when we get gas if the Stations Cover isn't marked with a height, my wife jumps out to make sure we are OK, we have had several that we could tell just by looking were too low and don't pull in. The more you drive it the better you will get at estimating the height of obstacles. Also pay attention to low bridge signs on some of the freeway exits, not a usual thing, but it does occur where a bridge on a small street exit may not have the clearance.
Mike & Charlotte
2014 Newmar Canyon Star 3610
Orange County, California