OOOH, Ouch,..sad! I cut a length of quarter-round the height of my cab roof and went around cutting any branch that was near that height. Got most of 'em but maybe I'll start carrying the chainsaw when I go mowing for a while till I get the rest. Same with the ones that catch my mirrors, that really gets to me!!
Hope you intend to rebuild as that fan idea sounds good. Fortunately I have A/C in my cab, but could have used that idea over the years.
The best to you,
. . tug