In reply to Guy Hurst:
Cycled up to the lodge around 3 years ago. The road was good tarmac up to around the point where it meets the loch, then there was a stretch of maybe 1km which was distinctly worse (IIRC still old metalled road but in very bad condition with potholes / grit), than the remainder to the lodge was good tarmac again. We had mountain bikes which were fine, a hybrid might be ok if it doesn't have very skinny tyres and you're careful. However, even if you end up pushing the bike all of the rough bit, it would still be well worth taking the bike, time-wise.