It seems that you can prevent from going to LVL 2 Encounters in order to do some more LVL 1 encounters to get more items/experience/etc.
But once you have started doing LVL 2 encounters are you allowed to take LVL 1 encounters?
This came up in our game and for the moment we ruled it as alright because it seems that they are just slowing their own progress by not advancing on the track to the fortress. But then it seemed a bit unbalanced when someone was in LVL 3 encounters and they hit a Dead Zone Mountain region so they took a LVL 1 encounter and were able to get supplies without having to put up to much of a fight.
So to repeat the question. Are you allowed to take lower level encounters once you've begun taking higher level encounters.
Page 6 of the rule book:
"Once you enter a new section, you may not draw from the previous one". This is referring to encounter levels.
Good question, but I think it is pretty clear in that sentence (although "section" could be "level").
Hope that helps