I started mine in winter which helped with getting the shit ones done first but the biggest problem was trying to fit 200s in when I was trying to train and race TTs during the summer.
When the snow hit, I used home as a control with 2 different 'loops', meant I wasn't more than 50km from home, and it was all on gritted/cleared roads.
I had similar issues, almost resorted to taking a day off midweek in August to get mine done! Only 3 more to go though.