I'm certainly not an expert, as I only have one 50 miler under my belt. Mine was a spur of the moment decision about a month before the race.
Before signing up, my training was in the 30-35 mile range, with long runs in the 12 mile range. In the weeks leading up to the 50M, I did 52, 65, 77, 52, 45. Long runs were 15, 23, 30, with 20 the next day, and 12.
I also did a lot of walking, not included in those totals. To me the important things were: time on your feet, practice run/walk intervals, practice slow pace, and practice your nutrition. Since you're going slower, your body is burning fat rather than carbs. I used half turkey and jelly sandwiches, with a touch of ginger for its anti nausea properties, washed down with plain old Gatorade. I know: it sounds disgusting, but it worked for me.
I started off running 8 minutes (or 10, not sure) and walking 2 minutes. I quickly realized it made more sense to always walk the hills even if it wasn't time. I ended up walking most of the last 12 miles, running whenever I could.
Tips: go SLOW! Walk before you need to and eat before you're hungry.
My experience won't be much help on the drop bag. My 50M had a nice format: 6.5 mile loops, meaning every 6.5 miles you were back at the aid station and your car. I had so much gear, it looks like a family of 4 was camping. I changed socks, shirts, and hats at some point. I had plenty of Body Glide, sunscreen, and chap stick.
I finished in 11:36:##. My weak link was my feet. Legs felt OK, stomach felt OK, mind was OK, feet wanted to stop. I had one small blister that I was able to pop. My foot problems were not friction related; they just hurt. I ended up with about 4 black toes and lost a big toenail a couple of weeks later. Until the 50M, I never had toenail problems. I suspect my feet swelled from all that time upright and started banging against my shoes. The next day, I felt better than after a marathon.
(Edited to clarify foot problems.)