The next three months are the worst months of the year for a groundsman. Try to keep machinery off the pitches as much as possible. If you can, chain harrow or Quadraplay the pitches in two directions - the earlier in the week the better. That way, you have replaced the divots, put a pattern on the pitch and will have no need to go back onto the pitch during the week apart from to mark it out. If there is a cold snap I advise that you roll the pitch as this will help save matches by flattening the surface. However; do not use anything heavier than your mowers to avoid compaction. A well-grassed pitch will cope with frost better than a bare one. It may be useful to work with the club committee to make a policy decision on whether the or not you will play on the pitches if they are frost bound.
If you need to play a game and the forecast is for frost use a roller after you have chain harrowed the pitch or use a Quadraplay. Have a little stock pile of sand which you can use to top dress any areas that may be rutted after scrums and the like. Use the same sand that you top dressed with. Two men and a wheel barrow can move and spread a fair amount of sand. If you work as a team you can be chain harrowing and spreading sand at the same time. If however you decide that it is too hard to play, keep off the pitch and let the referee see that it is rutted and unplayable.