Baljc
1) re shoes, I didn't really notice.
2) The tables are very frequent, around every 2m or 3km. They've got water, sport drink and pepsi as well as some food - salted potato, sweets, biscuits, sandwiches, oranges. I think they would be adequate unless you want anything very specific. Hardly anyone carries a pack. You would need to take your own gels
It's no problem to go further than marathon distance once you've accepted you need to slow down to cover the extra distance. Accepting walking breaks are a plan for success is also necessary.