Blowing out Main Line

I come back from the north this weekend (-40f). I drain the system when I leave. The distance of the pump to the check valve is approx. 20'. 1 1/4" line. The check valve and point are located outside. I was told to blow out the main line from the check valve back to the pump (drain port) This would mean from the outside to the inside. As you can imagine hauling a compressor outside in -40 weather with 4' of snow is not fun. I would like to blow out the main line through the drain port of the pump to the check valve (as a drain port). This would eliminate alot of hassle and all could be done from the inside of the place.. Further more gravity helps out with the draining. I worry however about damaging the seals in the pump. Any suggestions.