I have been reading advice from long riders about saddle blankets, after my saddle pad rubbing Cognac behind the saddle on our two day training ride, the advice is to use wool saddle blankets (which can also double up as an extra blanket for me in a bunkhouse) and also to take a spare foam sleeping mat. These are lightweight to carry and if you get a saddle sore, they can be cut to size, cut a hole over the sore spot and it relieves the pressure from the spot so that i can heal.
Hopefully with my new saddle bags and if I start using a wool saddle blanket I will not get any more rubs, but if I was to get a rub on my trip, then it could add a lot of time onto my journey as I haven't scheduled in any rest days, although I have tried to plan shorter days after days that I know will be long or strenuous.
If I do get any rubs or injuries on my trip, obviously it depends on the circumstances, but I plan to wait it out, until we are ready to continue. In this instance I will try to push all our accommodation stops back.
A few quotes from the Long Rider's Guild website:
"Its not the kilometres that kill your horse. Its the kilograms."
" Historically there have been two major reasons that equestrian journeys have failed - saddle sores and bad feet"