Thanks for writing in with your questions. The best way to approach this sort of random schedule is to just focus on base training: High volume of low to moderate intensity training and some strength training (either in a gym or on a hill). The bigger your base of fitness in these two areas the better these weekend mountain trips will go. When you know 1 week in advance of something ‘big’ you can reduce the training load for that week or a few days to allow you to feel more fresh and less tired for that special day.
As for how long it takes to recovery from these things: Only you can know this. You have to be honest with yourself about how you feel for the days after. Jumping back to full training loads too soon will only make you weaker not stronger. Find a simple test liek the ‘stairs test’ of some light run to assess your recovery. When in doubt you should be more conservative.