Rations was never a problem. First, I just didnt mind it, then I simplified it, by just assuming PCs would be always buying food for their journeys and subtract an average ammount for week from their money. Of course, when they spent too much time on the road without reaching a city, I would rule they ran out of food, if I saw a good idea for a little game hunting.
One of the things that i had troule with was with travelling. During my first DMing experiences, I wasn't sure how to handle it. say the party would spend 2 months on the road. I was always worried to throw things on the road so their travel was uneventful, but I wasnt good at that.
I also had a hard time tracking down their Hit POints.
Now-a-days, I still find myself making n00b questiosn about rules, but mainly that's because I only DM online and find myself "forced" to DM D&D 3.5, which is not a system I am very fond of, so I am not very knowledgeable of the rules. And because I have been DMing mostly D&D 3e and 3.5e, i have now forgotten a good part of the rules from AD&D 2nd ed, so I find myself making n00b questions about both. =P